PhD Samuel Guillemot
email: samuel.guillemot@univ-brest.fr

Professor Bertrand Urien
email: bertrand.urien@univ-brest.fr

Legacy writing among the elderly: conceptual bases, dimensioning and a proposed scale for measuring motivations

Keywords: Legacy writing, elderly, intergenerational transmission, identity

This article concerns a relatively unknown phenomenon in marketing that has become, however, extremely popular among older adults: legacy writing. While the writing of "egodocuments" has been the subject of many studies in gerontology, sociology and, above all, literature, research in marketing has yet to examine its specific components. The purpose of this article is to identify the concept of legacy writing and propose an initial scale to the academic and managerial community for measuring the motivations underlying this practice.

Two sets of data collected with questionnaires (202 and 508 responses) have been used to develop and confirm the validity of a scale consisting in twenty items, divided into six dimensions (flattering the ego, mending the ego, being remembered, sharing, transmitting, and bearing witness). This research offers a contribution to the theoretical corpus on special objects and intergenerational transmission. It demonstrates that the meaning of a special object is not exclusively restricted to symbolic references that may be lost or denatured, but others that are explicit and inscribed at the very core of the object.

INTRODUCTION

"Would you like to share your experience, let your passions live on a little longer, but have neither the time nor motivation to write? The biography writer is here to help you. He immerses himself in your life and emotions. A story emerges from your memories...The biography writer can help you write a book in your image" 1 . This excerpt from a French website, written by one of the many private biographers on the market, illustrates the current popular interest in memoirs and autobiographies. The trend seems particularly strong among the elderly if we consider the numerous advertisements designed to meet the need for remembrance and transmission published in media targeting seniors. Many older individuals have engaged in mentally constructing a coherent life story. While some do indeed transform these thoughts into action, most believe they will someday write their memoirs, without taking the idea any further. Since writing an autobiography is a long and difficult process, some people need a "ghost writer", while others merely require guidance. The market for socalled "biographical" services is highly diversified, rapidly developing and relatively unstructured. We can deplore numerous cases of abusive practices. For example, certain private writers have no qualms about charging €8,000 to "deliver" a biography, while others offer a similar service for only €2,500 2 . Indeed, from both a managerial and academic standpoint, this is a field that is relatively unknown in marketing research. While the writing of "ego-documents" (biographies, autobiographies, diaries, memoirs, etc.) [START_REF] Gusdorf | Lignes de vie -Les écritures du moi (tome 1)[END_REF] has been the subject of many studies in gerontology, sociology and, above all, literature, research in marketing has yet to examine its specific components. This study concerns more specifically the experience of aging [START_REF] Guiot | Un cadre d'analyse du processus de vieillissement et de son influence sur le comportement d'achat du consommateur âgé[END_REF]. Subjective aging and the prospect of a limited future trigger coping mechanisms that can lead to a search for self-continuity and desires for self-preservation and/or extension.

While marketing has examined self-extension, self-preservation and intergenerational transmission [START_REF] Belk | Possessions and the extended self[END_REF][START_REF] Wallendorf | My favourite things": a cross-cultural inquiry into object attachment, possessiveness, and social linkage[END_REF][START_REF] Price | Older consumers' disposition of special possessions[END_REF][START_REF] Curasi | Maybe it is your father's oldsmobile: the construction and preservation of family identity through the transfer of possessions[END_REF], these studies have mainly focused on the symbolic preservation and transmission of the self through "special or cherished" possessions. However, the significance of the possession transmitted is fragile and may be altered by the person who receives it [START_REF] Epp | Enacting the family legacy: how family themes influence consumption behaviour[END_REF]. Interestingly, legacy writing offers a way to circumvent the problem of symbolic meanings. Could it be an intergenerational practice aimed at transmitting important 1 Anne Thomas, ecrivain-biographe.com 2 Magazine Lire, n°353, March 2007 information to descendants? Or is it a means of identification that consists in highlighting and preserving a life rich in memories, experiences and meaning? More generally speaking, what are the motivations behind legacy writing? These are a few of the many questions raised by this field of investigation.

The purpose of this study is to identify the concept of legacy writing and propose an initial scale to the academic and managerial community for measuring the motivations underlying this practice. We will limit our investigations to the elderly, due to the frequency of the practice at this stage in life. In an initial phase, starting from an interdisciplinary review of the literature, we propose a brief socio-historical approach to the writing of "egodocuments", outlining how the elderly are particularly concerned by these practices and identifying the nature of the different motivations behind legacy writing. In a second phase, we will propose constructing and confirming the validity of a scale in order to measure the motivations of legacy writing by means of a double quantitative study. Finally, we will discuss the contributions, managerial implications and limitations of this study, as well as the avenues for future research it suggests.

THEORETICAL FRAMEWORK

After recapping its socio-historical aspects and defining the concept of legacy writing, we will examine its different internal motivations as identified in the source disciplines.

Socio-historical aspects

"Ego-documents" developed in the 18 th century, parallel to the process of "individualization". At that time, the privileged classes, who had access to writing, were less influenced by the dominant ideas of the Church and State and gradually became aware of the singularity of the individual. Little by little, the traditional worldview crumbled, collective obligations became weaker and access to a better education drew the individual into a world of values, standards and conflicting practices. In this "era of the individual", which encouraged everyone to perform as well as possible in every aspect of life while remaining "true to oneself", personal writings developed [START_REF] Delory-Momberger | Histoire de vie et recherche biographique en éducation[END_REF]. The narrative can help reconcile these multiple lives, by selecting and linking events. Generally, the distinction is made between fragmentary writings (such as a personal diary) and retrospective writing about the self (such as memoirs or autobiographies). In the first case, there is a search for meaning, which is highly prized among adolescents seeking their true identity, for example, while the second case involves construction of meaning from personal temporal events (Pineau and Le Grand, 1993;[START_REF] Carron | Écriture et identité, pour une poétique de l'autobiographie[END_REF]. This second approach fits particularly well with the aging process. Indeed, when they reach retirement age, individuals often tend to think about their lives and what they have become [START_REF] Erikson | Identity and the life cycle: selected papers[END_REF][START_REF] Butler | The Life Review: an interpretation of reminiscence in the age[END_REF][START_REF] Castelnuovo-Tedesco | Reminiscence and nostalgia: the pleasure and pain of remembering[END_REF]. This soul searching tends to shed new light on certain events and focus on important facts that the individual will seek to preserve and eventually transmit to others [START_REF] Guiot | Un cadre d'analyse du processus de vieillissement et de son influence sur le comportement d'achat du consommateur âgé[END_REF]. In addition, a common fear among the elderly is to see memories, experiences and other meanings accumulated over a lifetime dispersed after death [START_REF] Curasi | Maybe it is your father's oldsmobile: the construction and preservation of family identity through the transfer of possessions[END_REF][START_REF] Epp | Enacting the family legacy: how family themes influence consumption behaviour[END_REF].

The motivations behind legacy writing

Many disciplines are concerned with the practice of legacy writing. Sociology focuses on its role in identity construction [START_REF] Delory-Momberger | Histoire de vie et recherche biographique en éducation[END_REF], while gerontology examines its specific influence on coping with aging [START_REF] Argentin | Parler de son temps : récits de vie et ateliers d'écriture[END_REF]. The literary research stream devoted to the autobiography as a genre is concerned with analyzing narratives [START_REF] Lejeune | Le pacte autobiographique[END_REF][START_REF] Lejeune | Signes de vie : Le pacte autobiographique[END_REF]. A summary of this interdisciplinary review reveals six generic motivations:

Flattering the ego

The need for recognition is described as one of the pillars of personal writings. The narrative offers an opportunity for the writer to present himself to others [START_REF] Madelénat | Moi, biographe : m'as-tu vu ?[END_REF], to highlight a positive career and emphasize the aspects of his life he deems worthy of interest such as his successes, skills, academic or professional achievements, etc. [START_REF] Rioul | Le désir autobiographique, Conférence prononcée le 7 mars dans le cadre de l'Université du Temps Libre[END_REF]. In the extreme, this approach can be perceived as a form of narcissistic gratification since the facts are selected and biased, offering a self-apology and even citing oneself as "a reference or example" [START_REF] Miraux | L'autobiographie, écriture de soi et sincérité[END_REF].

Mending the ego

In addition to flattering the author, the narrative can often be a means of evacuating discontentment. We must not overlook the liberating power of story telling, which allows the writer to express bottled up emotions and make a clean breast of things [START_REF] Zanone | Triple démarche pour une transformation de soi. Psychanalyse, socioanalyse et autobiographie[END_REF].

Similarly, legacy writing offers the opportunity to refute "wrongful" accusations [START_REF] Hubier | Littératures intimes : les expressions du moi, de l'autobiographie à l'autofiction[END_REF], to set the record straight, to formulate a correction or denial [START_REF] May | L'autobiographie[END_REF]. Among "illustrious" writers, Rousseau was one of the first, in his time, to use his confessions to justify his conduct.

Being remembered

In the final years of life, legacy writing is a way of accepting the inevitable. Indeed, an in-depth analysis of his own experience allows the individual to portray himself as the hero of a unique and busy life [START_REF] Tarman | Autobiography: the negotiation of a lifetime[END_REF] and to take stock of what he wishes to leave behind, either in terms of a material estate or the experiences of a lifetime [START_REF] Vercauteren | L'animation dans les établissements pour personnes âgées, Manuel des pratiques professionnelles, Pratiques gérontologiques[END_REF]. From this standpoint, the life narrative is intended to outlive its author, as it allows the writer to impart what he wishes to be remembered for [START_REF] Cristini | Mémoire et autobiographie[END_REF].

Sharing

In nursing homes for the elderly, legacy writing is highlighted as a means of communication, a vector for exchanges and sharing [START_REF] Janvier | Atelier d'écriture et personnes âgées, Aux vendanges de la vie[END_REF], as it enables the creation of social ties between residents [START_REF] Billé | Le lien social au coeur de la prévention, Le traitement social de la vieillesse, La gérontologie en actes[END_REF][START_REF] Ribes | Mémoire générationnelle et identité[END_REF], between residents and staff [START_REF] Ross | Lesson of life[END_REF][START_REF] Blanchard | Rejouer les évènements de vie du grand âge[END_REF][START_REF] Trueman | Exploring community nurses' perceptions of life review in palliative care[END_REF] and even between residents and their own families [START_REF] Argentin | Parler de son temps : récits de vie et ateliers d'écriture[END_REF]. Thus, by evoking his life story, the narrator can try to create a sort of intimacy with his readers.

Transmitting

Legacy writing is also described as a means of transmission that offers an opportunity to "hand on the torch", to situate one's life in a line of ancestors and present these long lost relatives to younger members of the family. It is also a way of playing a new social role, which was once reserved for "elders", of preparing the young generation for the future [START_REF] Billé | À quoi servent les grands-parents ? Des grands-parents pour introduire au « sacré[END_REF].

Bearing witness

Finally, legacy writing can be used to preserve certain information from one generation to another. The difference with the previous function, which is limited to the family circle, lies in the desire to make a broader contribution to the collective memory. Indeed, the narrator can, for example, describe an old-time profession that was lost due to new technologies or become the village historian [START_REF] Lecarme | L'autobiographie[END_REF]. Relating events in which one took part or to which one was a privileged witness is a way of representing a collective destiny [START_REF] Zanone | Triple démarche pour une transformation de soi. Psychanalyse, socioanalyse et autobiographie[END_REF]. Finally, legacy writing allows the narrator to contribute to "universal knowledge", to help tomorrow's sociologists, historians and researchers.

Thus, legacy writing can be considered a process of constructing meaning from personal temporal events. The story can focus -or not -on the narrator, be written for contemporaries or for posterity. It stems from deep motivations that we have identified during our review of the literature. Therefore, flattering the ego and bearing witness are proposed in the literary genre while mending the ego is highlighted in both the fields of literature and sociology. Gerontology emphasizes the importance of motivations for sharing, transmitting and being remembered.

CREATING AND VALIDATING A SCALE FOR MEASURING THE MOTIVATIONS BEHIND LEGACY

WRITING

We started by a careful examination of the construct's field that we shall detail later on. This led us to select a mathematical model with reflexive indicators. We then went on to perform a series of steps, inspired by Churchill's paradigm (1979) and the remarks of [START_REF] Rossiter | The C-OAR-SE procedure for scale development in marketing[END_REF] while adapting them to current analysis tools (structural equations). These are summarized in Table 1 and discussed in the following paragraphs.

<Insérer le Table 1 -The stages involved in constructing and validating the scale >

The nature of the construct For [START_REF] Rossiter | The C-OAR-SE procedure for scale development in marketing[END_REF], the definition of a construct is based on three components: the object (legacy writing), the attribute (motivations) and the rater entities (people age 60 or older). In other words, we wanted to measure the motivations of individuals age 60 or over for legacy writing. More specifically, we proposed six latent constructs representing the different dimensions of these motivations (flattering the ego, mending the ego, being remembered, sharing, transmitting and bearing witness). In order to apprehend these constructs, we linked them to observable manifestations, for example, "I want to write so people can learn things about me that I am proud of" for the construct flattering the ego.

At this point, the crucial question is the relationship between these latent constructs and the variables measured. Indeed, we must bear in mind that an error in the direction of causality between a manifest variable and a latent construct during measurement model specification leads to an inappropriate purification procedure for the items [START_REF] Diamantopoulos | Index construction with formative indicators: an alternative to scale development[END_REF][START_REF] Jarvis | Critical review of construct indicators and measurement model misspecification in marketing and consumer research[END_REF][START_REF] Crié | De l'usage des modèles de mesure réflexifs ou formatifs dans les modèles d'équations structurelles[END_REF]. The articles of [START_REF] Jarvis | Critical review of construct indicators and measurement model misspecification in marketing and consumer research[END_REF] and [START_REF] Jarvis | Critical review of construct indicators and measurement model misspecification in marketing and consumer research[END_REF] First, in following Howel, Breivik and Wilcox (2007a) and [START_REF] Bagozzi | On the meaning of formative measurement and how it differs from reflective measurement: comment on Howell, Breivik, and Wilcox[END_REF], we estimate, unlike [START_REF] Jarvis | Critical review of construct indicators and measurement model misspecification in marketing and consumer research[END_REF], that constructs are not formative or reflexive by nature and the design of a measurement model is more of an epistemological choice on the part of the researcher than a feature of the construct itself. We therefore place our study within a realist perspective (Howell, Breivik and Wilcox, 2007a), in that the mental construct under consideration exists outside its measurements. Furthermore, the use of reflexive indicators is advisable, considering the inherent limitations of formative constructs, formulated in an explicit manner in recent contributions [START_REF] Diamantopoulos | The error term in formative measurement models: interpretation and modelling implication[END_REF][START_REF] Bollen | Interpretational confounding is due to misspecification, not to type of indicator: comment on Howell, Breivik and Wilcox[END_REF][START_REF] Franke | Proportional structural effects of formative indicators[END_REF]Howel et al., 2007a;[START_REF] Diamantopoulos | Advancing formative measurement models[END_REF]. Among these, the fact that the error term does not represent a measurement error, but the surplus meaning of the construct that is not captured by its indicators, is a major drawback since, in practice, it is impossible to detect all the possible causes of a construct (Howel, Breivik and Wilcox, 2007b). The formative measures would also be subject to errors in interpretation (ibid).

Secondly, [START_REF] Wilcox | Questions about formative measurement[END_REF] suggest that the same list of items can be conceptualized in a formative or reflexive manner, depending on the instructions the researcher gives to the respondents. If the questions are formulated based on past actions ("I wrote my autobiography because..."), the indicators will a priori be formative of legacy writing (they are causes). On the other hand, if we evoke future events ("I would like to write an autobiography in order to…"), judgment is based on hypothetical actions and the indicators become reflections of the construct [START_REF] Wilcox | Questions about formative measurement[END_REF]. In the first case, we obtain an "objective" construct, while in the second case the reflexive indicators offer a construct that is subjective in nature, corresponding to the psychological constructs frequently used in studies of consumer behavior [START_REF] Bollen | Interpretational confounding is due to misspecification, not to type of indicator: comment on Howell, Breivik and Wilcox[END_REF].

Creating and validating items

We conducted a qualitative study with eight individuals who had written their life story, and eight others who were thinking of writing one. The qualitative study, which will not be developed here, enabled the emergence of the six motivations identified in the previous sections. We extracted a corpus of 96 verbatims characterizing these six types of motivation.

Based on these verbatims and the literature, and taking into consideration the methodological points outlined above, we generated a list of 77 items representing reflections of each motivation.

To ensure face validity and reduce the initial list of items, these were submitted to a panel of five experts, all experienced researchers in consumer behavior and all familiar with the construction/manipulation of measurement scales. Following the procedure recommended by [START_REF] Jolibert | Marketing research, Méthodes de recherche et d'études en marketing[END_REF], the experts received a definition of the construct and its components. Each was asked to evaluate items as "highly", "sufficiently" or "not very" representative of the dimensions to which they were assigned. The experts also gave their opinion as to the clarity of the propositions. Therefore, certain items were reworded. Only items deemed "highly representative" by a majority were selected, except if they were considered "not very" representative by one of the experts. In the end, 36 items (or 46.75% of the initial number) were selected (see Appendix A1).

Methodology for collecting data

Two data sets were collected. The first set was collected in the summer of 2009 and allowed us to purify indicators of the scale through exploratory principal components analyses using SPSS software. The second was collected in the autumn of the same year and was used for a confirmatory factor analysis with EQS software. The respondents were asked to what extent they agreed with statements listed in random order (Appendix A1) according to a 5point Likert scale ranging from "completely disagree" to "completely agree". The number of levels was set at five since older respondents are generally not comfortable with more complex response formats [START_REF] Mezred | La réminiscence : concept, fonctions et mesures. Adaptation française de la Reminiscence Functions Scale[END_REF]. The questionnaires were distributed in situ, in places where people concerned by the study are most likely to congregate (retirement homes, clubs and associations for retirees, adult education courses, etc.). Considering the personal nature of certain questions, we preferred to use a self-administered questionnaire. In all, 710 useable responses were collected, 202 and 508 for the first and second data sets respectively. All the people questioned were over 60 years old. This threshold age was selected because many specialists in health, psychology and marketing agree that, along with retirement, it marks the beginning of "old age" for most people [START_REF] Bresay | Vieillir[END_REF][START_REF] Fry | Cross-cultural comparisons of aging[END_REF][START_REF] Guiot | Un cadre d'analyse du processus de vieillissement et de son influence sur le comportement d'achat du consommateur âgé[END_REF]. The average age of the respondents was 71.28 (with a standard deviation of 8.6) for the first data set and 68.80 (with a standard deviation of 6.84) for the second. The two samples were composed, respectively, of 56% and 64% women. Levels of education were quite heterogeneous, indicating the social diversity of the samples (Appendix A2).

Collecting the first data set and purifying the items

After eliminating questionnaires with too much missing data and checking for the absence of outliers [START_REF] Hair | Multivariate data analysis[END_REF], the first data set produced 202 useable responses.

Analysis of the correlations matrix of the 36 variables (not provided here) demonstrates that 94% of correlations are significant. Considering the level of intercorrelations, it is not surprising to obtain an MSA score of 0.89. This means that the indicators have something in common and warrant use of a process to reduce information [START_REF] Kaiser | Little Jiffy Mark 4[END_REF]. A series of principal components analyses enabled us to identify a set of latent dimensions. Since the components were assumed to be correlated, we used an oblique oblimin rotation of the factor axes to facilitate interpretation. Only the factors with eigenvalues greater than 1 were selected. Finally, we deleted the items that did not cluster on any of the axes, or, on the contrary, saturated on several factors in a comparable way.

According to these criteria, 6 PCA were required to obtain a stable solution. At this stage, the 14 remaining items clustered around 4 factors. The items we had generated representing the dimensions transmitting and flattering the ego disappeared when the scale was purified (Appendix A1). For transmitting, the way the items were formulated was called into question. In order to generalize the statements and avoid special cases, we eliminated words pertaining to family life so as not to exclude respondents without children. However, the items formulated this way were too general and did not refer explicitly to values, roots and family history, aspects that are, according to the literature and our qualitative interviews, the ones most commonly transmitted. For the dimension flattering the ego, the definition submitted to the experts was questioned, since it insisted on its narcissistic character (to talk about the things I have done) rather than "recognition" which also plays a role (to show sides of myself others may not know). In light of these comments, we generated new items for these two components (9 in all). These items were validated by three new experts and we added them to the 14 others in order to collect another set of data (Appendix A1).

The second data set and the emergence of the factor structure

The second data set provided 508 useable responses. After checking for the absence of outliers, we again purified the items according to the rules defined in the previous phase. The analysis rendered 6 factors for 20 items. Only the latent roots of the first five factors were greater than 1. The scree test shows a first break after the fifth component (eigenvalue 1.07) and a second one, not quite as sharp, after the sixth (eigenvalue 0.93). We kept the sixth dimension as it is justified from a theoretical standpoint. Indeed, it also emerges in randomly drawn sub-samples. The final result is a scale consisting in 6 dimensions with 3 to 4 items each. The coefficients range from 0.79 for the dimension entitled sharing to 0.83 for bearing witness (Table 2).

< Insérer Table 2 -Final factor structure of the 20 items>

Validating the factor structure At this point, our objective was to confirm the factor structure that had emerged through structural equation modeling. Confirmatory factor analysis (CFA) supposes a normal distribution of the data. Mardia's coefficient (G2, P) shows an absence of multivariate normality. It has a value of 85 (normalized estimate = 32), much greater than the acceptable limit of 3 set by [START_REF] Bentler | EQS 6 structural equations program manual[END_REF]. In fact, in the area of social sciences, data rarely has a normal distribution. The Satorra and Bentler statistic (1988), available under EQS software as "Robust methods", produces coefficients of significance corrected according to the intensity of non-normality.

The model tested consists in 6 latent constructs that are allowed to covary freely. This produced good indices of fit considering the degree of complexity and the number of observations. For a model with 20 items and 508 observations, the CFI should be greater than 0.92 and the RMSEA under a threshold of 0.07 [START_REF] Hair | Multivariate data analysis[END_REF]. This is the case here: besides an ² of 340 for 155 degrees of freedom (p = 0.00), the value of the CFI is 0.95 and that of the RMSEA is 0.05 (confidence interval of 90%: [0.042-0.056]). Considering the high degree of correlations between the constructs, we believed it was important to test alternative models and more specifically the five-factor model that had emerged in the beginning. The indices of fit for the latter are under commonly accepted thresholds and consequently lower than those for the 6-factor model (² = 557; dof =160 (p = 0.00); CFI = 0.90; RMSEA = 0.07). Similarly, several other models were tested, for example the unidimensional model (² =1194; dof =170 (p = 0.00); CFI =0.74; RMSEA = 0.11), but none produced fit indices as satisfactory as the six-dimensional one. Therefore, the six dimension factor structure produced the best results and was finally selected.

Reliability, convergent and discriminant validities of the measurement model

In this phase we will examine the psychometric qualities of the instrument by testing its reliability and convergent and discriminant validities. Face validity has already been confirmed as the items were selected by experts. The nomological validity will be examined in the following section.

Reliability is confirmed when all the indicators measure the same construct in a more or less equal manner. Here this is ensured by the coefficients for Jöreskog's rhô, which are all greater than 0.7 (Table 3), a commonly accepted threshold [START_REF] Fornell | Evaluating structural equations models with unobservable variable and measurement error[END_REF].

The convergent validity corresponds to the capacity of a measure to provide results close to other measures of the same trait. This is confirmed when: (1) the z-test associated with each factor contribution is greater than 1.96 (a significant link between a latent construct and its indicators) and ( 2) each indicator shares more variance with its construct than with its error term [START_REF] Steenkamp | The use of LISREL in validating Marketing construct[END_REF]. In reality, this condition is fulfilled if the average variance extracted  vc ) for each dimension is greater than 0.5. All the latent constructs meet these two conditions (Table 3).

<Insérer Table 3 -Evaluation of reliability and convergent validity >

The discriminant validity is ensured when two theoretically different constructs are clearly distinguished empirically. Thus, the correlations between the two constructs must be less than the square root of their  vc , which is the case here (Table 4). It should be noted, however, that certain correlations are high, for example between the components of mending the ego and being remembered (0.70). Nevertheless, the indicators within a single dimension share more variance with each other than with those of another dimension.

<Insérer Table 4 -Evaluation of discriminant validity and correlations between constructs>

Second-order factor analysis and nomological validity

Since the correlations between constructs were all important and significant (from 0.50 and 0.70), we performed an exploratory second-order factor analysis. This caused a single higher order factor to emerge. The confirmatory analysis produced good indices of fit (² = 381; dof = 164 (p = 0.00); CFI = 0.95; RMSEA = 0.05). The standardized loadings between the first-order constructs and the higher order factor are all significant and greater than 0.7.

The model with a single second order factor was therefore accepted (Table 5). This means that the six motivations share a common concept, which would be an overall motivation to write one's life story. From a theoretical standpoint, this appears to fit with a hierarchical conception of motivation [START_REF] Vallerand | Toward a hierarchical model of intrinsic and extrinsic motivation[END_REF][START_REF] Vallerand | Deci and Ryan's self-determination theory: A view from the hierarchical model of intrinsic and extrinsic motivation[END_REF][START_REF] Vallerand | Le modèle hiérarchique : Une analyse intégrative des déterminants et conséquences de la motivation intrinsèque et extrinsèque[END_REF]. The overall motivation behind legacy writing would be expressed in the form of six contextual motivations (bearing witness, transmitting, etc). Once again, we followed Howel, Breivik and Wilcox (2007a) in considering that this global motivation exists independently from its measure. The first order latent constructs, representing the different motivations, therefore constitute reflections of the second order factor.

<Insérer Table 5 -Second-order factor analysis>

As for nomological validity, it is ensured if we can observe, empirically, that an individual with these motivations for legacy writing does intend to write his life story. Indeed, it aims to confirm the definition of the construct by studying the correlations between the construct and other manifestations that are intrinsically attached to it in a quasi tautological way [START_REF] Jolibert | Marketing research, Méthodes de recherche et d'études en marketing[END_REF]. The intention of writing one's life story has been operationalized using a single item scale. This is sufficient if the construct is conceptualized in a concrete and unique manner by the respondent [START_REF] Rossiter | The C-OAR-SE procedure for scale development in marketing[END_REF][START_REF] Bergkvist | Comparaison des validités prédictives des mesures d'un même construit des échelles mono-item et des échelles multi-items[END_REF], which is the case of behavioral intentions (Jarvis et al., 2004). With the help of the semi-structured interviews we conducted (not dealt with here), we were able to distinguish different specific stages in commitment to writing a life story: not interested, interested but does not plan to write a life story, plans to write a life story one day, extremely interested in getting started or already involved in the writing process These modalities were proposed to the respondents during the quantitative study. In order to avoid an artificial correlation linked to the order in which the questions were administered, two other scales were inserted between the items measuring motivations for legacy writing and the intention to write a life story. In addition, while the scale thus designed is not metric, the data can be estimated within a structural equations model as the modalities reflect an increasing degree of commitment [START_REF] Byrne | Structural equation modeling with EQS: basic concepts, applications, and programming[END_REF]. In such a case, estimation using the maximum likelihood method with Satorra-Bentler's adjusted indices (1988) guarantees reliable results [START_REF] Distefano | The impact of categorization with confirmatory factor analysis[END_REF][START_REF] Bentler | EQS 6 structural equations program manual[END_REF].

The results obtained indicate a significant correlation between the two constructs (r = 0.50; z-test = 10.16), thus confirming the nomological validity of the scale.

CONTRIBUTIONS, MANAGERIAL IMPLICATIONS, LIMITATIONS AND PERSPECTIVES FOR FUTURE

RESEARCH

Contributions

The aim of this study was to identify the concept of legacy writing, define its dimensions and propose a scale for measuring its underlying motivations (Appendix A3). To our knowledge, this is the first theoretical and empirical study on the subject in terms of consumer behavior. Starting from a review of the literature and two quantitative data sets, we created a reliable and valid scale for measuring the motivations behind legacy writing among the elderly. The scale consists in 20 items, divided among six dimensions (flattering the ego, mending the ego, being remembered, sharing, transmitting and bearing witness).

This scale represents a first step towards understanding the concept of legacy writing. It will help provide an empirical understanding of the relationship between motivations underlying this practice and other variables within the concept's nomological network.

Furthermore, this study enriches our understanding of self-extension and self-preservation "tactics" [START_REF] Price | Older consumers' disposition of special possessions[END_REF] and intergenerational transmission strategies among the elderly [START_REF] Curasi | How individuals' cherished possessions become families' inalienable wealth[END_REF][START_REF] Curasi | Maybe it is your father's oldsmobile: the construction and preservation of family identity through the transfer of possessions[END_REF]. Legacy writing, using any media (a book, CD, etc.), thus appears to be a new form of "special object" whose symbolic part is lost for the benefit of a specific function. We should note that "special" or "precious" objects (wedding rings, grandpa's pen, etc.) are "vehicles" for family and individual histories [START_REF] Curasi | How individuals' cherished possessions become families' inalienable wealth[END_REF][START_REF] Bergadaà | La personne âgée : son attitude face à l'idée de mort, le cadre temporel de son action et son sens de l'objet[END_REF] and possess a certain number of functions similar to those we have identified for legacy writing: a form of recognition, a souvenir of important moments in life, an eye witness account of exceptional events, a record of specific skills and abilities [START_REF] Price | Older consumers' disposition of special possessions[END_REF]. It also has a therapeutic value and provides, in particular, a point of reference and stability [START_REF] Wapner | Cherished possessions and adaptation of older people to nursing homes[END_REF]). Finally, it can be a means for transmitting individual and family values.

When it is offered as a gift or left to a person who is able to preserve its meaning, it constitutes a means of being remembered [START_REF] Price | Older consumers' disposition of special possessions[END_REF] and is a form of intergenerational transmission [START_REF] Goldberg | Réaliser une boîte à souvenir[END_REF]. Yet, while a life story can be considered a special object, it remains quite specific. Transmission of special object is often considered a symbolic transmission of the self. The information transmitted is therefore limited to fleeting memories generated by the object in question once its owner has passed. However, a life story goes much further by offering the transmission of an explicit, more or less faithful and sometimes idealized, summary of the self. The explicit nature of the information contained in a life story enables it to play a major role in the transmission of intergenerational memory and offers a partial remedy to the fragile meaning attached to objects, as emphasized in our introduction [START_REF] Epp | Enacting the family legacy: how family themes influence consumption behaviour[END_REF].

Managerial implications

While biographical services remains a niche market, the potential for development is nevertheless real. Indeed, while collecting the second data set (508 individuals), 12.8% of the respondents had already written a life story or were currently writing their memoirs. In addition, more than 50% had already thought about it, but were discouraged by the difficulty of the task, which is undoubtedly why 42% stated they were interested in some form of training (18% in "co-production" services 3 ). In this case, marketing can play a fundamental role. If it succeeds in motivating some of the individuals interested in legacy writing to get started, our field will have played an important role in transmission of intergenerational memory. Along these lines, certain anthropologists, while observing growing indifference to rituals surrounding death, predict the creation of a new type of necropolis. Mnemonic monuments [START_REF] Larcher | Mnémothèques pour l'an 2000[END_REF]) would be used to conserve the memory of the deceased rather than their bodies or physical remains. Here there seems to be a potential for new services targeting seniors.

Furthermore, by identifying the different motivations behind legacy writing, service providers will be able to segment their offers since a person who wants, above all, to transmit his family history does not have the same needs or expectations as someone who wants mainly to relate his experience of racism, for example. Fundamentally, training services (workshops, coaching, etc.) are suitable when the process is as important as the result, for example, when the narrative is guided by a desire to mend the ego and the writing process is a form of "healing". Conversely, "co-production" services are more suitable when the narrative is more important than the writing process. For example, when the autobiography addresses the needs of a community (transmitting and bearing witness) the underlying idea is to serve others, by whatever means.

3 Private biographers. We use the term "co-production" here because the consumer supplies the raw material (memories) and the service provider contributes his writing skills.

There are obvious ethical questions involved that need to be taken into consideration.

We have already pointed out, at the beginning of this article, prices for similar services can vary considerably. It is important to bear in mind that managerial ethics are based on moral values, compliance with laws, codes of business conduct and personal responsibility [START_REF] Katz | New sex for old: lifestyle, consumerism, and the ethics of aging well[END_REF]Bergadaà, 2004;[START_REF] Urien | Attitude face à la mort et comportement d'ajustement des consommateurs âgés : Vers l'élaboration d'une réponse marketing[END_REF]. This scale should be used with caution, in an effort to meet the needs of elderly consumers, not to take advantage of them.

Limitations and perspectives for future research

Several limitations can be raised concerning this study. One concerns the external validity of the scale. Its validity was confirmed using a sample of elderly persons. Our results can be considered a first step as the scale must be compared against other representative data for the general population in order to increase its validity. Our second data set was indeed mostly made up of people attending continuing education courses at "Universités du Temps Libre", who have a higher level of education than the general French population. We can also question whether the French biographical model can be transferred to other cultures. Each culture has its own representations of the self, with its own concepts for conceiving of and expressing personal, family and cultural experiences. According to [START_REF] Roche | Le modèle autobiographique est-il exportable ? Exemples au Maghreb[END_REF], for example, the autobiography exists in North African countries, but often contains a mix of real and fictional events and poetry. From a more general standpoint, an extension of this study internationally, to include other cultures, could examine both the stability of the different motivations behind legacy writing identified here and the types of biographical services available.

In this study we have not examined cohort effects [START_REF] Meredith | Cohort effects[END_REF][START_REF] Zemke | Generations at work: managing the clash of veterans, boomers, Xers and nexers in your workplace[END_REF]. The socio-historical events that take place during the years when important life choices are made (age 15 to 25) shape the attitudes and behaviors of a given generation [START_REF] Préel | Le choc des générations[END_REF]. Thus, the 1920-1930 cohort, which took part in and survived WW2, does not have the same story to tell and transmit as the 1945-1955 cohort, which grew up in a booming economy [START_REF] Lalive D'épinay | Mémoire de l'histoire et appartenance générationnelle des personnes âgées[END_REF]. However, we believe that generational differences would not affect motivations, but rather the content of the story itself.

This point remains to be clarified. Furthermore, we did not examine the reasons people prefer written over oral transmission [START_REF] Sanchez | Discours oraux, discours écrits, les seniors et l'écriture de soi[END_REF]. Thus, our "functionalist" approach to life storiesand its methodological dimension, which consisted in questioning people about their motivations for writing an autobiography -can be called into question. This approach privileges the conscious and intentional motivations behind legacy writing and does not focus on the meaning individuals attribute to their own behavior. A comprehensive approach to legacy writing therefore offers an interesting avenue for future research.

It would be interesting now to examine other variables that could affect biographical behavior such as feelings of self-efficacy [START_REF] Bandura | Social foundations of thought and action: a social cognitive theory[END_REF], generativity [START_REF] Mcadams | A theory of generativity and its assessment through self-report, behavioural acts, and narrative themes in autobiography[END_REF][START_REF] Urien | L'anxiété face à la mort et son influence sur le comportement du consommateur[END_REF]Kilbourne, 2007, 2011), or even reminiscence [START_REF] Webster | Construction and validation of the reminiscence function scale[END_REF][START_REF] Haber | Life Review: implantation, theory, research and therapy[END_REF]. [START_REF] Price | Older consumers' disposition of special possessions[END_REF], as well as Curasi, [START_REF] Curasi | How individuals' cherished possessions become families' inalienable wealth[END_REF], present transmission of special objects as a desire for self-preservation after death, a form of symbolic immortality. However, these authors do not make any distinctions in their presentation of the final moment [START_REF] Urien | L'anxiété face à la mort et son influence sur le comportement du consommateur[END_REF]. Yet, there are different attitudes toward personal death that generate either anxiety or acceptance. More specifically, [START_REF] Et Kravetz | Fear of personal death: attribution, structure, and relation to religious belief[END_REF] and [START_REF] Et Snowden | Fear of personal death and positive life regard[END_REF] present a multidimensional model of fear of personal death (fear of loss of self-fulfillment, fear of self-annihilation, fear of loss of social identity, fear of consequences of death to family and friends, fear of transcendental consequences, fear of punishment in the hereafter). An important research question would concern the impact of the type of attitude towards personal death on the nature and intensity of motivations to write a life story.

Another research topic would consist in comparing the biographical tendencies of different generations. Thus, the same type of approach could be envisaged in order to understand the quest for identity among adolescents through personal diaries and blogs, or to understand social networks such as Facebook. Self-production as a relationship technique [START_REF] Cardon | La production de soi comme technique relationnelle. Un essai de typologie des blogs par leurs publics[END_REF]) is a highly contemporary field of investigation. The field of application for biographical services could also be expanded to, for example, business biographies (d'Almeida and Merran-Ifrah, 2005) or more generally corporate histories, as can be observed in this excerpt from a major regional newspaper 4 : "In a time of crisis, History is a safe investment. As a biographer, Hélène's books are true corporate sagas. In the region, many entrepreneurs use her services." The following table presents the items generated and selected by the experts.

-The number corresponds to the position of the statement on the scale. For example, the item "to tell my family and friends what I would like to be remembered for" within the dimension being remembered was administered in the 15 th and 8 th place, respectively, when collecting the two data sets. -The mention "E" indicates an item that was eliminated after PCA.

-Items marked with an asterisk (*) were generated and administered during collection of the second data set.

  are at the heart of the "reflexive vs. formative" debate. After reading recent contributions published in special issues of Psychological Methods (2007; n° 12, 2) and the Journal of Business Research (2008; n° 61), we decided to use a reflexive model (where the measured variables are effects of the constructs) for several reasons.

4

  Ouest-France, November 2008.

  79); transmitting (= 0.81) and bearing witness (with ML (Maximum Likelihood)). "Robust" statistics corrected for non-normality -² = 340; df =155 (p = 0.00); CFI = 0.95; RMSEA = 0.05 -All the alternative models tested produce less satisfactory fit indices > 0.80 (reliability) -Structural coefficients significantly linked (z-test > 1.96) and  vc > 0.5 (convergent validity) -The correlations between the two constructs squared are less than their  vc (discriminant validity) 7-Second-order factor analysis and nomological validity -Existence of a second-order factor (² = 381; dof =164 (p = 0.00); CFI = 0.95; RMSEA = 0.05); structural coefs > 0.70; representing the "global" motivation for legacy writing -The correlation between this global motivation and the real intention to write a life story is 0.5 (nomological validity)

I would like to write my life story… 1 st data set 2 nd data set

  Legacy writing consists in using your memories to write your life story. Please indicate if the following statements concern you or not (strongly disagree, disagree, neither agree nor disagree, agree, strongly agree). to leave a trace of the way we lived, so that future generations can picture our way of life to leave a testimonial, because it is a sort of heritage you pass on to future generations to preserve certain aspects of my culture that are disappearing to record, somewhere, certain things that must not be lost

	to tell the truth about certain things that happened in the past	8		11
	to justify certain things I did in the past	11		15
	Being remembered so I can highlight the things I would like to be remembered for in order to choose what I would like to leave for posterity because it is important for me to know how my family and friends will remember me after my death to tell my family and friends what I would like to be remembered for because I believe leaving something behind is a way to achieve a form of immortality so my family and friends remember me after my death because writing about one's life is a way of being remembered so that people will remember what I have done after my death Bearing witness to help future generations understand how the world has changed to leave a trace of the way we lived, so that future generations can picture our way of life to confess to certain things because I want to talk about certain things that are important to me Flattering the ego because there are things about my life that are worth knowing to show how I became the person I am today to talk about myself and the things I have done in my life because there are things I have done that should be recognized to talk about the interesting things I have done in my life *to highlight things I have done and am proud of *to highlight things about myself that others are not necessarily aware of *to show people who don't know me who I really am *to show how I started out and how I became the person I am today Transmitting to prevent the younger generation from making the same mistakes as I did to transmit certain essential values to the younger generation to show the younger generation their roots by transmitting my life story and experiences, I am trying to help others because I want the younger generation to understand what one should, or should not, do *to retrace my family history *to tell the younger generation about family members who have passed away *to transmit family values I would like to write my life story… Being remembered (= 0.83) so my family and friends remember me after my death to tell my family and friends what I would like to be remembered for so that people will remember what I have done after my death Bearing witness (= 0.83) Sharing (= 0.79) to create a certain intimacy with readers to broaden my circle of acquaintances to create ties with certain people Mending the ego (= 0.81) to help me clarify a period in my life to tell my side of the story concerning certain things that happened in the past 30 17 9 15 6 34 12 20 27 3 35 26 1 28 22 36 21 10 23 5 25 *for the younger members of the family who want to know about their roots Instructions: to tell the truth about certain things that happened in the past to leave a testimonial, because it is a sort of heritage you pass on to future generations 13 to justify certain things I did in the past	E E E E E E E E E E E E E E E E E	8 4 12 5 2 17 19 21 22 1 18 20 9	E E E
	because I think that expressing our thoughts about society can enable future generations to understand the world in which they will live Flattering the ego (= 0.80)	29	E
	because leaving behind an account of our times is like a gift for future generations to talk about the interesting things I have done in my life	31	E
	because there are certain things that should be preserved and transmitted from one generation to another to highlight things I have done and am proud of to highlight things about myself that others are not necessarily aware of	33	E
	to preserve certain aspects of my culture that are disappearing	24		13
	because we need make sure some things are not forgotten Transmitting (= 0.81)	4	E
	to record, somewhere, certain things that must not be lost to tell the younger generation about family members who have passed away 18 to transmit family values Sharing for the younger members of the family who want to know about their roots		16
	to create a certain intimacy with readers	19		6
	to broaden my circle of acquaintances	2		10
	to create ties with certain people	14		14
	because it is important to talk about life's difficulties, to show people who are going through the same things that they are not alone	16	E
	Mending the ego
	to help me clarify a period in my life	7		3
	to tell my side of the story concerning certain things that happened in the past	32		7

Table 1 -The stages involved in constructing and validating the measurement scale

 1

	Stages performed	Key results
		-There are 6 motivations behind legacy writing, identified in the
	1-Specifying the construct's field	literature and confirmed during a qualitative analysis (not developed here) -These indicators are effects of the construct. Churchill's paradigm
		is adapted
		-16 semi-structured interviews (not developed here)
	2-Creating and	-77 items generated based on the literature and qualitative
	validating items	interviews
		-36 items selected by a panel of experts (face validity)
	3-Collecting the first data set and purifying the items	-202 responses -22 items eliminated through 6 PCA (oblique rotation) -The dimensions transmitting and flattering the ego do not emerge: 9 new items are generated representing these dimensions
		-508 responses
	4-The second data set and the emergence of the factor structure	-3 items eliminated through 3 PCA -20 items cluster around 6 dimensions: Flattering the ego (= 0.80

); mending the ego (1); being remembered (); sharing (= 0.

Table 2 -Final factor structure of the 20 items

 2

	Communality Factor 1 Factor 2 Factor 3 Factor 4 Factor 5 Factor 6

Table 3 -Evaluation of reliability and convergent validity

 3

		Reliability Convergent validity
	Dimensions		z-tests	 vc
	Being remembered	0.82	z > 20	0.63
	Bearing witness	0.84	z > 16	0.57
	Sharing	0.80	z > 16	0.57
	Mending the ego	0.82	z > 13	0.53
	Flattering the ego	0.81	z > 13	0.59
	Transmitting	0.83	z > 16	0.61

Table 4 -Evaluation of discriminant validity and correlations between constructs

 4 The square roots of  vc are represented on the diagonal. The other values correspond to correlations between constructs.

		Being remembered	Bearing witness	Sharing	Mending the ego	Flattering the ego	Transmitting
	Being remembered	0.79
	Bearing witness	0.67	0.75
	Sharing	0.62	0.63	0.75
	Mending the ego	0.70	0.56	0.65	0.73
	Flattering the ego	0.69	0.54	0.62	0.69	0.77
	Transmitting	0.58	0.69	0.50	0.55	0.51	0.78

Table 5 -Second-order factor analysis First-order factors

 5

		Loadings
		(standardized)
	Being remembered	0.853
	Bearing witness	0.780
	Sharing	0.768
	Mending the ego	0.813
	Flattering the ego	0.779
	Transmitting	0.713


Robert Joumard
email: joumard@inrets.fr

Keywords: Environment, definition, impact, assessment, typology, source, process, target, sustainability

Definitions of the environmental dimension of sustainable development are usually general and the variety of impacts rarely considered. A correct representation of the full range of effects is necessary for an accurate and transparent environmental sustainability assessment. Environmental impacts and their characteristics are described through the concept of causal chains between a source and a final target. Its parameters are the source target, time and distance scales, and the final target. The scientific disciplines involved in defining indicators are considered. This analysis is based on research on environmental impacts resulting from transport. It allows us to define 49 independent causal chains that address all effects. They are organized into a hierarchy of 27 aggregated chains and 8 groups, as the usual binary classification (quality of life/natural heritage, present/future generations, reversibility, local/global) lacks meaning.

Introduction

The economic and grey literature (applied research, international organisations, local applications) on sustainable development presents most of the environmental impact assessments conducted about policies, plans, programmes, projects or technologies. How are environmental issues considered and how is sustainable development's environmental pillar defined in such literature?

Economic papers limit discussion of environmental questions to greenhouse gases or a few other well-known effects. They unconsciously reduce the scope to effects for which simple-to-use assessment tools are available, without justifying such simplification. Often, health, safety or landuse issues are considered alongside the environment, inferring that they are not part of the environment itself (for example Wolfram, 2004;SSNC, 2006;[START_REF] Droulers | DURAMAZ, un système d'indicateurs de développement durable en Amazonie brésilienne[END_REF]. Some authors, nevertheless, consider that it is of utmost importance to take into account health, safety and land-use effects, regardless whether these are included within the environmental or social pillar. Although it is important, of course, to consider all environmental impacts, classifying each impact has political meaning, because it implicitly defines economic, social, and environmental issues. Citizens, and often policy makers, are unable to consider social and environmental issues in detail while keeping a macro perspective at the same time. A precise definition of each pillar is needed to arrive at transparent evaluations and clear political choices.

When only some impacts or concerns are considered, without any justification whatsoever (for example [START_REF] Droulers | DURAMAZ, un système d'indicateurs de développement durable en Amazonie brésilienne[END_REF], discussing the relevance of these impacts is impossible. For instance, [START_REF] Lardé | Théorie de la régulation et développement durable : analyse de la diversité nationale des profils environnementaux et des politiques environnementales[END_REF] do not justify their choice of 12 criteria for designing the environmental profiles of 21 countries. The output, a country typology, depends on the criteria used. In addition, the 12 criteria are considered equally important, whereas the statistical tools used discard well-correlated parameters. Thus, the CO and CO2 emissions criteria, which are clearly not well correlated, play the same role in defining environmental profiles although today CO is considered a secondary pollutant and CO2 the primary source parameter. This undoubtedly builds a typology, but we question its meaningfulness.

Besides the use of environmental sustainability indicators, an alternative approach increasingly used in industry is life cycle assessment (LCA). LCA aims to evaluate the environmental impact of the entire life cycle of a product, process or service (ISO 14040, 2006). One of the advantages of LCA is that it is a well-established, standardised method that also includes an impact assessment phase life cycle impact assessment (LCIA) where potential effects are quantified and totalled. Several tools are based on LCA, such as building for environmental and economic sustainability [START_REF] Lippiatt | Using BEES to select cost-effective green products[END_REF], the ecological scarcity or Eco-factors 2006 methods [START_REF] Frischknecht | The Ecological Scarcity Method -Eco-Factors 2006. A method for impact assessment in LCA[END_REF] or the ReCipE method [START_REF] Goedkoop | ReCiPe 2008 -A life cycle impact assessment method which comprises harmonised category indicators at the midpoint and the endpoint level[END_REF]. LCA has been used, for instance, to estimate environmental impacts from fuels made from biomass [START_REF] Von Blottnitz | A review of assessments conducted on bio-ethanol as a transportation fuel from a net energy, greenhouse gas, and environmental life cycle perspective[END_REF][START_REF] Zah | Life Cycle Assessment of Energy Products: Environmental Assessment of Biofuels[END_REF], from water systems [START_REF] Lundin | A life cycle assessment based procedure for development of environmental sustainability indicators for urban water systems[END_REF] or from buildings [START_REF] Assefa | Environmental assessment of building properties-Where natural and social sciences meet: The case of EcoEffect[END_REF][START_REF] Scheuer | Life cycle energy and environmental performance of a new university building: modelling challenges and design implications[END_REF]. In these methods and studies, the environmental effects considered vary widely. Without explanation, comparisons between methods and between studies are difficult.

Although most of the papers discuss the environment, they almost never deal with it as a whole. It remains an idea that is not defined clearly and precisely. Without such a definition, the idea can be interpreted at will, adapted so widely that it sometimes remains only a vague expression, and, at worse, used only to justify one's project or policy.

On the contrary, [START_REF] Washington | Steden op koers? Stadsmonitor voor Leefbare en Duurzame Vlaamse Steden[END_REF] or [START_REF] Van Assche | Une méthode participative pour mesurer la durabilité urbaine[END_REF], stressed the need to define first a matrix view for a sustainable and viable city to provide a normative framework for choosing the relevant indicators. Then, they went on to define almost 200 indicators of a sustainable city for Flemish urban areas. They later remarked that each indicator must be connected clearly with an item of the matrix view.

Environmental issues are sometimes varied and questionably structured. Thus, the environmental objectives of sustainable development, as presented for instance by Swedish municipalities (Gudmundsson, 2007, p. 37), merge primary objectives (for example, environmental quality) with objectives for solutions (for example, less use of non-renewable resources, more use of public transport). The differences are imperceptible and objectives are not ranked.

A second definition of the environmental issue is more global and top-down. For instance, OECD (2001) distinguishes between development criteria -whose environmental aspects deal with environmentally conditioned welfare and the role of air, noise and water quality in the health of present generations -and sustainability criteria, whose environmental aspects address conditions of long-term development thanks to access to critical natural resources, ecosystems and climate stability. Economists often consider this last criteria as natural capital, in other words as a resource used by humans for producing economic goods. This resource is an ecosystem, that is the association between a physico-chemical and an abiotic (the biotope) on the one hand and the conditions that allow the latter to live (the biocenosis), including fossil resources, on the other. When this resource is destroyed, it can be renewed to a certain extent. The environmental issue is about resource reserves, resource flow and the capacity of the biosphere to support the effects of human activities (carrying capacity). The causal frameworks for describing the interactions between society and the environment adopted by the OECD -pressure-state-response or PSR -and by the European Environment Agency -driving forces-pressures-states-impacts-responses or DPSIR - (EEA, 2009) seem well applicable to this meaning with a pressure representing a flow.

In parallel, the environment is often understood as the quality of our physical environment or the quality of life. It is difficult to consider only flows and pressure when looking at a calm area with pure air and water, or a beautiful landscape [START_REF] Job | Agriculture, environnement et développement durable : une analyse des effets des politiques contractuelles en France' [Agriculture, environment and sustainable development: Analysis of the impacts of contract policies in France[END_REF][START_REF] Gudmundsson | Sustainable Mobility and incremental change -Some building blocks for IMPACT[END_REF].

Both these global meanings of the environment correspond roughly to the concept of internal and external territorial sustainability defined by [START_REF] Wackernagel | Our ecological footprint: Reducing human impact on the Earth, Gabriola Islands[END_REF]. Internal sustainability consists in protecting one's direct environment and living area, whereas external sustainability consists in protecting the world as a whole.

These synthetic, global and top-down definitions of the environment's sustainability pillar are not based on explicit analyses of environmental impacts, objectives or issues. Such definitions are too vague to be useful for describing actual environmental issues or impacts on the environment or for designing environmental impact indicators. An exhaustive list of environmental impacts or objectives is necessary to present a full picture, especially if the clear aim is to identify the most important issues mentioned by [START_REF] Black | Toward a measure of transport sustainability[END_REF] or [START_REF] Borken | Indicators for sustainable mobility -a policy oriented approach[END_REF], and those that are important in decision making [START_REF] Ahvenharju | Operationalising Sustainable Transport and Mobility: The System Diagram and Indicators[END_REF][START_REF] Nicolas | Towards sustainable mobility indicators: application to the Lyons conurbation[END_REF][START_REF] Zietsmann | Sustainable Transportation: Conceptualization and Performance Measures[END_REF]. How can key issues be identified with a top-down approach, without a comprehensive assessment of all relevant ones? Below, we try to describe precisely environmental issues in the transport sector. We begin with a review of the literature and then present the concept of a causal chain. Finally, we analyse the relevance of global descriptions of the environmental issue. This research is detailed in a specific report (Joumard et al., 2010).

Precise description of environmental issues in the transport sector

In the literature

Environmental or ecological impacts are often listed in transport literature (for example [START_REF] Usepa | Indicators of environmental impacts of transportation -Highway, Rail, aviation and maritime transport[END_REF]OECD, 1996;Swedish EPA, 1996;EC, 2001;OECD, 2002;EEA, 2002;[START_REF] Borken | Indicators for sustainable mobility -a policy oriented approach[END_REF][START_REF] Ahvenharju | Operationalising Sustainable Transport and Mobility: The System Diagram and Indicators[END_REF][START_REF] Goger | Un indicateur d'impact environnemental global des polluants atmosphériques émis par les transports [An aggregated indicator of air pollution impacts involving transport[END_REF][START_REF] Goger | A method of building an aggregated indicator of air-pollution impacts[END_REF][START_REF] Calderon | Integrated assessment of environmental impact of traffic and transport infrastructure[END_REF][START_REF] Joumard | Transport project evaluation methodology within the framework of sustainable development[END_REF], in public surveys conducted at a national [START_REF] Boy | Les représentations sociales de l'effet de serre (8 e vague d'enquête)[END_REF] or international level (EC, 2008), or in building literature [START_REF] Assefa | Environmental assessment of building properties-Where natural and social sciences meet: The case of EcoEffect[END_REF][START_REF] Bunz | Survey of Sustainable Building Design Practices in North America, Europe, and Asia[END_REF][START_REF] Lippiatt | Using BEES to select cost-effective green products[END_REF][START_REF] Scheuer | Life cycle energy and environmental performance of a new university building: modelling challenges and design implications[END_REF]. See some examples Table 1. Their definition is rarely clear or precise; the lists are often heterogeneous -merging sources, intermediate states of the environment, such as local air or water quality, and final impacts on the environment, such as visual effects. For instance, [START_REF] Usepa | Indicators of environmental impacts of transportation -Highway, Rail, aviation and maritime transport[END_REF] or [START_REF] Ahvenharju | Operationalising Sustainable Transport and Mobility: The System Diagram and Indicators[END_REF] list mainly the pressures or the principal consequences of the transport system on the environment, rather than environmental impacts (although the consequences are labelled as impacts). While some effects are often mentioned -such as climate change, photochemical pollution or noise -others, including soil erosion, vibration, light pollution, hydrologic and hydraulic risks, odours, soiling or visibility, are rarely discussed. Dimming, risk of fire or electromagnetic pollution are not mentioned in the 13 references studied. Some impacts listed are broad, combining several effects on the environment, such as air pollution or soil protection and landscape. Some lists, like this one from the European directive (EC, 2001), repertory the final targets, but with redundancies such as biodiversity/fauna and flora or population/human health. Environmental impacts also depend on the society in which they occur. Esoh Elame ( 2004), for instance, shows how the values and beliefs of a given African people's cultural heritage determine to a large extent the items of nature they want to protect. In Sub-Saharan Africa, the natural capital cannot be dissociated from the cultural capital. To speak about nature means to speak about culture, and vice versa. [START_REF] Roqueplo | Pluies acides : menaces pour l'Europe [Acid rain: Threats for Europe[END_REF] and [START_REF] Brüggermeier | Le dépérissement de la forêt (Waldsterben) : construction et déconstruction d'un problème d'environnement' [Forest decline (Waldsterben): construction and deconstruction of an environmental issue[END_REF] have noted similar relationships for forests and acid rains in Germany. More generally, [START_REF] Lammel | La pollution atmosphérique comme objet cognitif : diversité des perceptions' [Atmospheric pollution as cognitive object: diversity of perceptions[END_REF] show how the idea of the environment itself differs between holistic societies, such as Totonaque, Inuit or Badui ones, and individualistic/analytic societies such as Western ones.

In Western countries at least, the environmental issue is a personal construct, based on an individual perception of its components mediated by our senses and completed by intellectual elements from technical or scientific news we receive through education and the media (Brüggemeier, 2002;[START_REF] Van Staëvel | La pollution sauvage [Illegal pollution[END_REF]. This personal construction is thus now structured by a long-term view.

One of the most structured descriptions of the environmental issue consists in using objectives to discuss the environment, as [START_REF] Keeney | Value-focused thinking: a path to creative decision-making[END_REF] proposed. [START_REF] Rousval | Aide multicritère à l'évaluation de l'impact des transports sur l'environnement[END_REF] and [START_REF] Rousval | Évaluation de l'impact des transports sur l'environnement : quels modèles utiliser ?[END_REF] applied this method to the environment, and arrived at a hierarchy of 24 goals by interviewing local decision makers and environmental specialists. This list is nevertheless heterogeneous, merging final targets (fauna, flora), processes (greenhouse effect) and intermediate impacts (soil pollution). Its main advantage, like the approach Van Assche, [START_REF] Van Assche | Une méthode participative pour mesurer la durabilité urbaine[END_REF] or [START_REF] Washington | Steden op koers? Stadsmonitor voor Leefbare en Duurzame Vlaamse Steden[END_REF] took, is the use of a systemic perspective and a clear logic.

Table 1

Environmental impacts listed by 13 references and their correspondence with the proposed causal chains

The concept of causal chains

We seek to adopt a systemic approach to environmental issues that will consider all an environmental policy's impacts and objectives. We propose to extend the pressure-state-impact structure from EEA to the concept of causal chains between a cause and a final target, with the possibility of a succession of cause-impact pairs. A causal chain can be defined as an ordered sequence of events or issues, in which one event or issue in the chain causes the next. A good example is the greenhouse effect: greenhouse gas emissions are a first cause, which, by physical phenomenon, increase the earth's temperature, changing global and local climates, affecting agriculture and sea levels, leading to consequences for the whole biocenosis, including humans.

Impacts such as odours, soiling, visibility, habitat fragmentation, visual quality of landscape and loss of cultural heritage cannot be explained by a mechanistic view of flow and carriage capacity. To cover all impacts, the concept of causal chains has to be much wider than a reserve or flow problem inspired by physics. Any type of process can be considered: cultural, psychological, psychophysical, biological and, of course, physical.

A causal chain can be described through:

-The element(s) of a field of human activity (the transport system or any other sector), which is at the start of the process, taking into account the life cycle approach, i.e.: considering all the subactivities involved. For the transport sector, three main subsystems are involved (infrastructure, energy use, and vehicles), and for each of these, there are five types of activity (production, existence, use, maintenance, destruction).

-The final targets: Three targets (nature, humans, man-made heritage) and a pseudo-target, the earth (that encompasses the three targets, plus the atmosphere and oceans), are usually considered (e.g. [START_REF] Goger | Un indicateur d'impact environnemental global des polluants atmosphériques émis par les transports [An aggregated indicator of air pollution impacts involving transport[END_REF]. In addition, the Eco-indicator approach [START_REF] Brand | Weighting in Ecobalances with the ecoscarcity method -Ecofactors 1997[END_REF][START_REF] Goedkoop | The Eco-indicator 99: A damage oriented method for life cycle impact assessment[END_REF] includes three types of end point damage: resources, ecosystem quality and human health. The first two are subdivisions of the target 'nature'. The World Health Organisation [START_REF] Who | Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference[END_REF] defines human health as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." Therefore it is useful to distinguish health in its restricted meaning (absence of disease or infirmity) from so-called human well-being, because the processes are often different. Finally, we arrive at the target 'structure' presented in Table 2, with six targets: resources, ecosystems, human health in its restricted meaning, human well-being, man-made heritage, and the earth.

-The intermediary elements, that is the causal chain between human activity and the final target, to be described in detail. This can be summarized, for instance, through the scientific disciplines involved, the space and time scales, and the linearity and reversibility of the process. Scientific disciplines point to the process involved and who is able to discuss how representative an environmental impact indicator is. Space and time scales are important parameters in environmental studies [START_REF] Schulze | Transcending scales of space and time in impact studies of climate and climate change on agrohydrological responses[END_REF][START_REF] Huijbregts | Priority assessment of toxic substances in life cycle assessment. III: Export of potential impact over time and space[END_REF][START_REF] João | How scale affects environmental impact assessment[END_REF].

Process linearity shows how proportional the impact is to the source and how the latter is a major parameter for lessening the effect. Reversibility deals with sustainability, but one has to make a distinction between individuals and species. For example, the impact of traffic accidents is irreversible for humans who die in them, but not for society as a whole.

The causal chains allow for an all-encompassing assessment of relevant impacts known today (completeness). They should overlap as little as possible (independence). For instance, the chains "health effects of photochemical pollution" and "health effects of air pollution" are incompatible because they overlap.

Description of the causal chains

In line with the structure above, we have proposed a list of 49 environmental impact causal chains (especially due to the transport system) (see Table 3), a detailed description of which is given in Joumard and Gudmundsson (2010, annex 6, pp.325-366). The list of chains could be detailed further by dividing a chain into two or more chains, if it is felt processes or targets are not treated homogeneously. In addition some chains may be missing.

A first attempt to build a typology or structure of the 49 causal chains means merging them into 27 aggregated chains (by not considering the final target), and then into 8 groups (see Table 3). This typology suits usual structures and allows a simpler presentation of the whole.

To be practical, the number of categories should not be plethoric. Also, given the availability of data, some impacts can be merged and minor chains deleted. This must be done explicitly to allow others and future users to also perform such simplifications. The chain's structure must be as detailed as possible, because it is easier to merge and delete than to add processes. When classifying the chains according to A1/A2, B1/B2, C1/C2 or D1/D2, some cannot be differentiated according to such binary classification because they belong to both classes. For instance, most of the impacts on the ecosystems belong to A1 and A2, B1 and B2, and the effects on cultural heritage concern present and future generations. If we consider the irreversible character for society, that is the definitive modification of our life conditions on earth, the reversible/irreversible dichotomy is often the only obvious one. Several causal chains, and important ones indeed, are neither totally reversible nor totally irreversible. Thus the greenhouse effect is indeed reversible, but only after a few centuries. At an upper level, most of the 27 aggregated chains are combining detailed chains belonging to both categories.

As shown on Figure 1 for axes B and D, the four axes are continuous rather than discrete. The top-down approaches of the environment through simple and discrete classifications seem not to correspond to the reality of the impacts on the environment when the causal chains are considered. They cannot be used to characterise some causal chains. Reality is more complex than the allembracing approaches.

Figure 1

Ascending order of magnitude of the 49 causal chains' distance and time scales

Ascending order of magnitude of the 49 causal chains' distance and time scales (continued)

Conclusion

To describe the environmental impacts of an activity such as transport through a complete list of independent causal chains allows us to give a precise definition of the term 'environment'. However, in most cases, the list of chains we propose here is much too detailed to be used in a decisional context. The chains have to be aggregated, or some have to be retained and others dropped. That a comprehensive list exists allows for aggregation or choice with full knowledge of the facts.

The causal chain approach does not deal with interactions among chains, although in practice interaction could occur. For instance, we know that psychophysical effects are not independent from one another (such as impacts because of odours, noise or landscape quality). More generally, the processes leading to the different effects on a same final target (humans, or ecosystems) react to each other. Nevertheless, considering 'independent' chains is a first step before describing in depth the possible synergies.

The framework for the causal chains should be a universally valid analytical one. Nevertheless, the chains have been proposed to cover impacts on the environment only in the transport sector. Although most of them are not specific to transport, the same analysis should be carried out in other domains such as agriculture, energy production, industry, and so on. This would allow us to arrive at a universal framework different methods and tools could use to assess the environmental dimension of sustainability in different sectors.

The framework's main limitation is cultural. Adapted to Western societies, it may not be as suitable to Eastern, African or other societies where the concept of environment can be fundamentally different or inexistent in this form.

The precise description of environmental processes forms a powerful tool to assess environmental impact indicators. A priori, the closer to the final target the indicator is, the more precisely the final impact will be estimated. It is mainly a tool to define what precisely an indicator represents. Does it represent the final impact, or an intermediate one? How accurately is the process translated into the indicator role? Which relevant impacts do existing indicators ignore? Is there a possibility of double counting? When the aim is not only to reorganise information that exists, but also to build the tools necessary to represent environmental impacts, the all-inclusive description of the impacts is the first step of the process.

Table 2

 2 Typology of environmental impact targetsHow do these 49 causal chains fit in with the global descriptions of the environmental pillar of sustainable development seen above? These are related mainly to four types:

		Targets	Pseudo-target
		Resources	Earth: covers all the targets:
		Ecosystems: nature understood as	the three
	Nature	ecosystems, i.e. the association between a	previous
		physicochemical and abiotic (the biotope)	targets
		environment and a living community	(ecosystems,
		characteristic of the latter (the biocenosis)	humans and
	Human health: in a restricted meaning its health as defined by the WHO Human well-being Humans: humankind which we extract from nature and focus on	man made heritage) and physical environments
			such as the
	Man-made heritage: with a distinction made between common and historic	atmosphere
	buildings		and the oceans
	Table 3	Hierarchy of the 49 causal chains
	Noise and vibrations
	. Noise:
	. Disappearance of quiet areas (chain 1)
	. Annoyance and sleep disturbance to people due to noise (chain 2)
	. Effects on human health (restricted meaning) of noise (chain 3)
	. Noise and wildlife (chain 4)
	. Vibrations (chain 5)
	Accidents
	. Effect of traffic accidents on human health (chain 6)
	. Animal collision: Animal fatalities (chain 7)
	Air pollution
	. Sensitive air pollution
	. Odors (chain 8)
	. Soiling (chain 9)
	. Visibility (chain 10)
	. Direct (restricted) toxicity of air pollutants
	. Direct restricted effects on human health of air pollutants (chain 11)
	. Direct ecotoxicity on fauna and flora of air pollutants (chain 12)

. Photochemical pollution . Health effects of photochemical pollution (chain 13) . Loss of crop productivity due to photochemical pollution (chain 14) . Ecotoxicity on fauna and flora of photochemical pollution (chain 15) . Loss of cultural heritage due to photochemical pollution (chain 16) . (Secondary effects: greenhouse gas, acidification) . Acidification . Decrease of ecosystem health, loss of biodiversity due to acidification (chain 17) . Deterioration of historic buildings and other cultural assets due to acidific. (chain 18) . Eutrophication (chain 19) . Dimming (chain 20) . Ozone depletion . Health effects of ozone depletion (chain 21) . Ecotoxicity on fauna and flora of stratospheric ozone depletion (chain 22) Soil and water pollution . Pollution of soil, surface waters and groundwater . Effects on ecosystem health of pollution of soil, surface and groundwater (chain 23) . Health effects of pollution of soil, surface waters and groundwater (chain 24) . Recreational areas forbidden due to pollution of soil and surface waters (chain 25) . Maritime pollution . Effects on ecosystem health of maritime pollution (chain 26) . Health effects of maritime pollution (chain 27) . Recreational areas forbidden due to maritime pollution (chain 28) . Hydraulic changes and risks . Hydraulic changes (chain 29) . Hydraulic risk (chain 30) Impacts on land . Land take . Loss of natural habitats due to land take (chain 31) . Degradation of ecosystems due to land take (chain 32) . Modification of outdoor recreation areas, due to land take (chain 33) . Loss of cultural heritage due to land take (chain 34) . Habitat fragmentation . Loss of ecosystem health, loss of biodiversity, due to habitat fragmentation (chain 35) . Reduction of living areas of people, due to fragmentation (chain 36) . Soil erosion (chain 37) . Visual qualities of landscape/townscape (chain 38) Non-renewable resource use and waste handling . Non-renewable resource use (chain 39) . Non-recyclable waste (chain 40) . Direct waste from vehicles (chain 41) Greenhouse effect (chain 42) Other impacts

toward a new framework

 --------------------------------------------Robert Joumard is a Senior Scientist in the Laboratory Transport and Environment at the French National Institute for Transport and Safety Research (INRETS). He chaired the COST action 356 "EST -Towards the definition of a measurable environmentally sustainable transport", 2005-2010.

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