Contingent valuation controversies: Philosophic debates about economic theory

Journal of Socio-Economics

Volumn 36, Issue 2, 2007, Pages 204-232

  Veisten, Knut ^a  

^a NORWEGIAN UNIVERSITY OF LIFE SCIENCES   (Norway)

Author keywords

Contingent valuation; Neo classical economics; Positivism; Research programme

Indexed keywords

EID: 33846838698     PISSN: 10535357     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.socec.2005.11.049     Document Type: Article

References (146)

1. Adamowicz, W., Louviere, J.J., Swait, J., 1998. Introduction to attribute-based stated choice methods. Final Report to Resource Valuation Branch, Damage Assessment Center, National Oceanic and Atmospheric Administration, US Department of Commerce. Advanis, Edmonton, Canada. 44 p.
2. Ajzen I., Brown T.C., and Rosenthal L.H. Information bias in contingent valuation: effects of personal relevance, quality of information, and motivational orientation. Journal of Environmental Economics and Management 30 (1996) 43-57
3. Alvey J.E. A short history of economics as a moral science. Journal of Markets and Morality 2 1 (1999) 53-73
4. Ams P. Utility, publicity, and manipulation. Ethics 88 3 (1978) 189-206
5. Arrow K.J., Solow R., Leamer E., Portney P., Radner R., and Schuman H. Report of the NOAA panel on contingent valuation. Federal Register 58 (1993) 4601-4614
6. In: Bateman I.J., and Willis K.G. (Eds). Valuing Environmental Preferences: The Theory and Practice of the Contingent Valuation Method in the US, EU and Developing Countries (1999), Oxford University Press, Oxford 668
7. Becker G.S. The Economic Approach to Human Behavior (1976), The University of Chicago Press, Chicago 330 p
8. Becker G.S. Nobel lecture-the economic way of looking at behaviour. Journal of Political Economy 101 3 (1993) 385-409
9. Bergstrom J.C., Stoll J.R., and Randall A. The impact of information on environmental commodity valuation decisions. American Journal of Agricultural Economics 72 (1990) 614-621
10. Bishop R.G., and Heberlein T.A. Measuring values of extra-market goods: are indirect measures biased?. American Journal of Agricultural Economics 61 (1979) 926-930
11. In: Bjornstad J., and Kahn J.R. (Eds). The Contingent Valuation of Environmental Resources: Methodological Issues and Research Needs (1996), Brookfield, Vt. Edward Elgar, Cheltenham, UK
12. Blaug M. The Methodology of Economics. 2nd ed. (1992), Cambridge University Press, London
13. Blumenschein K., Johannesson M., Blomquist G.C., Liljas B., and O'Conor R.M. Experimental results on expressed certainty and hypothetical bias in contingent valuation. Southern Economic Journal 65 (1998) 169-177
14. Bockstael N.E., McConnell K.E., and Strand I. Recreation. In: Braden J.B., and Kolstad C.D. (Eds). Measuring the Demand for Environmental Quality (1991), North-Holland/Elsevier Science Publishers, Amsterdam 227-270
15. Boettke P.J. What is wrong with neoclassical economics (and what is still wrong with Austrian economics). In: Foldvary F. (Ed). Beyond Neoclassical Economics (1996), Edward Elgar, Cheltenham, UK
16. Boyle K.J., Bishop R., Hellerstein D., Welsh M.P., Ahearn M.C., Laughland A., Charbonneau J., and O'Conner R. Test of scope in contingent-valuation studies: are the numbers for the birds. Paper Presented at The World Congress of Environmental and Resource Economists (AERE/EAERE). Venice, Italy, June 25-27 (1998)
17. Boyle K.J., Desvousges W.H., Reed Johnson F., Dunford R.W., and Hudson S.P. An investigation of part-whole biases in contingent-valuation studies. Journal of Environmental Economics and Management 27 (1994) 64-83
18. In: Braden J.B., and Kolstad C.D. (Eds). Measuring the Demand for Environmental Quality (1991), North-Holland/Elsevier Science Publishers, Amsterdam 370
19. Brown T.C., Barro S.C., Manfredo M.J., and Peterson G.L. Does better information about the good avoid the embedding effect?. Journal of Environmental Management 44 (1995) 1-10
20. Brown T.C., Champ P.A., Bishop R.C., and McCollum D.W. Which response format reveals the truth about donations to a public good?. Land Economics 72 2 (1996) 152-166
21. Caldwell B.J. Beyond Positivism: Economic Methodology in the 20th Century (1994), Routledge, New York, London
22. Carmines E.G., and Zeller R.A. Reliability and validity assessment. Sage University Paper Series on Quantitative Applications in Social Sciences, Series No. 07-017 (1979), Sage Publications Inc., Beverly Hills, London
23. Carson R.T. Contingent valuation: theoretical advances and empirical tests since the NOAA panel. American Journal of Agricultural Economics 79 5 (1997) 1501-1507
24. Carson R.T., Flores N.E., Martin K.M., and Wright J.L. Contingent valuation and revealed preference methodologies: Comparing the estimates for quasi-public goods. Land Economics 72 1 (1996) 80-99
25. Carson R.T., Flores N.E., and Meade N.F. Contingent valuation: controversies and evidence. Environmental and Resource Economics 19 (2001) 173-210
26. Carson, R.T., Groves, T., Machina, M.J., 2000. Incentive and Informational Properties of Preference Questions. Draft, February 2000. Department of Economics, University of California, San Diego, 47 p.
27. Carson, R.T., Hanemann, W.M., Mitchell, R.C., 1987. The use of simultated political markets to value public goods. Discussion Paper 87-7. Department of Economics, University of California, San Diego.
28. Carson R.T., and Mitchell R.C. The issue of scope in contingent valuation studies. American Journal of Agricultural Economics 75 (1993) 1263-1267
29. Carson R.T., and Mitchell R.C. Sequencing and nesting in contingent valuation surveys. Journal of Environmental Economics and Management 28 2 (1994) 155-173
30. Chalmers A.F. What is This Thing Called Science?. 2nd ed. (1994), Hackett, Indianapolis
31. Champ P.A., and Bishop R.C. Donation payment mechanisms and contingent valuation: an empirical study of hypothetical bias. Environmental and Resource Economics 19 4 (2001) 383-402
32. Champ P.A., Bishop R.C., Brown T.C., and McCollum D.W. Using donation mechanisms to value nonuse benefits from public goods. Journal of Environmental Economics and Management 33 (1997) 151-162
33. Champ P.A., and Brown T.C. A comparison of contingent and actual voting behavior. Proceedings From W-133 Benefits and Cost Transfers in Natural Resource Planning, 10th Interim Report (1997)
34. Clark A.E., and Oswald A.J. A simple statistical method for measuring how life events affect happiness. International Journal of Epidemiology 31 (2002) 1139-1144
35. In: Cummings R.G., Brookshire D.S., and Schulze W.D. (Eds). Valuing Public Goods: The Contingent Valuation Method (1986), Rowman & Allanheld, Totowa, New Jersey
36. Cummings R.G., and Harrison G.W. Was the Ohio court well informed in its assessment of the accuracy of the contingent valuation method?. Natural Resource Journal 34 (1994) 1-36
37. Cummings R.G., and Harrison G.W. The measurement and decomposition of nonuse values: a critical review. Environmental and Resource Economics 5 (1995) 225-247
38. Cummings R.G., Harrison G.W., and Rutström E.E. Homegrown values and hypothetical surveys: is the dichotomous choice approach incentive compatible?. American Economic Review 85 (1995) 260-266
39. Cummings R.G., and Taylor L.O. Does realism matter in contingent valuation?. Land Economics 74 2 (1998) 203-215
40. Cummings R.G., and Taylor L.O. Unbiased value estimates for environmental goods: a cheap talk design for the contingent valuation method. American Economic Review 89 (1999) 649-665
41. Deaton A. Demand analysis. In: Griliches Z., and Intriligator M.D. (Eds). Handbook of Econometrics vol. 3 (1986), North-Holland/Elsevier Science Publishers, Amsterdam
42. Desvousges W.H., Hudson S.P., and Ruby M.C. Evaluating CV performance: Separating the light from the heat. In: Bjornstad J., and Kahn J.R. (Eds). The Contingent Valuation of Environmental Resources: Methodological Issues and Research Needs (1996), Brookfield, Vt. Edward Elgar, Cheltenham, UK
43. Desvousges W.H., Johnson F.R., Dunford R.W., Boyle K.J., Hudson S.P., and Wilson K.N. Measuring natural resource damages with contingent valuation: tests of validity and reliability. In: Hausman J.A. (Ed). Contingent Valuation: A Critical Assessment (1993), North-Holland/Elsevier Science Publishers, Amsterdam 91-159
44. Diamond P. Testing the internal consistency of contingent valuation. Journal of Environmental Economics and Management 30 (1996) 337-347
45. Diamond P.A., and Hausman J.A. On contingent valuation measurement of nonuse values. In: Hausman J.A. (Ed). Contingent Valuation: A Critical Assessment (1993), North-Holland/Elsevier Science Publishers, Amsterdam 1-38
46. Diamond P.A., and Hausman J.A. Contingent valuation: Is some number better than no number?. Journal of Economic Perspectives 8 4 (1994) 45-64
47. Diamond P.A., Hausman J.A., Leonard G.K., and Denning M.A. Does contingent valuation measure preferences? Experimental evidence. In: Hausman J.A. (Ed). Contingent Valuation: A Critical Assessment (1993), North-Holland/Elsevier Science Publishers, Amsterdam 41-85
48. Dickie M., Fisher A., and Gerking S. Market transactions and hypothetical demand data: a comparative study. Journal of American Statistical Association 82 (1987) 69-75
49. Duffield J.W., and Patterson D.A. Field testing existence values: an instream flow trust fund for Montana rivers. Paper Presented at the AERE Contributed Paper Session: Valuing Environmental Goods with Contingent Valuation, Allied Social Science Association Annual Meeting. New Orleans, January 4 (1991)
50. Eggertson T. Economic Behavior and Institutions (1990), Cambridge Survey of Economic Literature, Cambridge
51. Elster J. Ulysses and the Sirens: Studies in Rationality and Irrationality (1979), Cambridge University Press, Cambridge
52. Faber M., Petersen T., and Schiller J. Homo oeconomicus and homo politicus in ecological economics. Ecological Economics 40 (2002) 323-333
53. Frey B.S., and Stutzer A. What can economists learn from happiness research?. Journal of Economic Literature 40 (2002) 402-435
54. Friedman M. Essays in Positive Economics (1953), University of Chicago Press, Chicago
55. Galarraga I., and Markandya A. The use of hedonic methods to evaluate the economics of ecolabeling. Paper Presented at the Seminar of Environmental and Resource Economics. Girona, Spain, May (1999)
56. Getzner, M., 1999. Extending the Framework of Valuing Regional Biodiversity. University of Klagenfurt, Austria, unpublished paper.
57. Giraud K., Loomis J., and Johnson R. Internal and external scope in willingness to pay estimates for threatened and endangered wildlife. Journal of Environmental Management 56 3 (1999) 221-229
58. Green C., and Tunstall S. A psychological perspective. In: Bateman I.J., and Willis K.G. (Eds). Valuing Environmental Preferences: The Theory and Practice of the Contingent Valuation Method in the US, EU and Developing Countries (1999), Oxford University Press, Oxford 207-257
59. Gregory R., Lichtenstein S., and Slovic P. Valuing environmental resources: A constructive approach. Journal of Risk and Uncertainty 7 (1993) 177-197
60. Hanemann W.M. Willingness to pay and willingness to accept: how much can they differ?. American Economic Review 81 (1991) 635-647
61. Hanemann W.M. Valuing the environment through contingent valuation. Journal of Economic Perspectives 8 4 (1994) 19-43
62. Hanemann W.M., and Kanninen B.J. Statistical considerations in CVM. In: Bateman I.J., and Willis K.G. (Eds). Valuing Environmental Preferences: The Theory and Practice of the Contingent Valuation Method in the US, EU and Developing Countries (1999), Oxford University Press, Oxford 302-441
63. Hanley N., MacMillan D., Wright R.E., Bullock C., Simpson I., Parisson D., and Crabtree B. Contingent valuation versus choice experiments: estimating the benefits of environmentally sensitive areas in Scotland. Journal of Agricultural Economics 49 1 (1998) 1-15
64. Hanley N., and Milne J. Ethical beliefs and behaviour in contingent valuation surveys. Journal of Environmental Planning and Management 39 2 (1996) 255-272
65. Hanley N., and Munro A. Design bias in Contingent Valuation Studies: The Impact of Information (1991), Department of Economics, University of Stirling, Mimeo, Scotland
66. Hanley N., Spash C., and Walker L. Problems in valuing the benefits of biodiversity protection. Environmental and Resource Economics 5 (1995) 249-272
67. Harrison G.W. Valuing public goods with the contingent valuation method: a critique of Kahneman and Knetsch. Journal of Environmental Economics and Management 23 (1992) 248-257
68. Hausman D.M. The Inexact and Separate Science of Economics (1992), Cambridge University Press, Cambridge
69. In: Hausman J. (Ed). Contingent Valuation: A Critical Assessment. Contributions to Economic Analysis 220 (1993), North-Holland/Elsevier Science Publishers, Amsterdam 503 p
70. Hoehn J.P. Valuing the multidimensional impacts of environmental policy: theory and methods. American Journal of Agricultural Economics 73 (1991) 289-299
71. Hoehn J.P., and Randall A. A satisfactory benefit cost indicator from contingent valuation. Journal of Environmental Economics and Management 14 (1987) 226-247
72. Horowitz J.K. Preferences in the future. Environmental and Resource Economics 21 (2002) 241-259
73. Johannesson M., Liljas B., and Johansson P.-O. An experimental comparison of dichotomous choice contingent valuation and real purchase decisions. Applied Economics 30 (1998) 643-647
74. Johansson P.-O. The Economic Theory of Measurement of Environmental Benefits (1987), Cambridge University Press, Cambridge
75. Johansson P.-O. Altruism in cost-benefit analysis. Environmental and Resource Economics 2 (1992) 605-613
76. Kahneman D. The review panel assessment: comment. In: Cummings R.G., Brookshire D.S., and Schulze W.D. (Eds). Valuing Public Goods: The Contingent Valuation Method (1986), Rowman & Allanheld, Totowa, NJ
77. Kahneman D., and Knetsch J.L. Valuing public goods: the purchase of moral satisfaction. Journal of Environmental Economics and Management 22 (1992) 57-70
78. Kahneman D., and Ritov I. Determinants of stated willingness to pay for public goods: a study in the headline method. Journal of Risk and Uncertainty 9 (1994) 5-38
79. Kealy M.J., Montgomery M., and Dovido J.F. Reliability and predictive validity of contingent values: does the nature of the good matter?. Journal of Environmental Economics and Management 19 (1990) 244-263
80. Kiefer N. Microeconomic evidence on the neoclassical model of demand. Journal of Econometrics 25 (1984) 285-302
81. Knetsch J.L. Environmental valuation: some problems of wrong questions and misleading answers. Environmental Values 3 4 (1994) 351-368
82. Kolakowski L. Alienation of Reason: A History of Positivist Thought (1968), Doubleday, New York (translated from Polish by Guterman, N.)
83. Kolstad C.D., and Braden J.B. Environmental demand theory. In: Braden J.B., and Kolstad C.D. (Eds). Measuring the Demand for Environmental Quality (1991), North-Holland/Elsevier Science Publishers, Amsterdam 17-40
84. Kopp R.J. Why existence value should be included in cost-benefit analysis. Journal of Policy Analysis and Management 11 1 (1992) 123-130
85. Kriström B. Spike models in contingent valuation. American Journal of Agricultural Economics 79 3 (1997) 1013-1023
86. Kriström B., and Riera P. Is the income elasticity of environmental improvements less than one?. Environmental and Resource Economics 7 (1996) 45-55
87. Lakatos I. Falsification and the methodology of scientific research program. In: Lakatos I., and Musgrave A. (Eds). Criticism and the Growth of Knowledge (1970), Cambridge University Press, London
88. Lancaster K.J. A new approach to consumer theory. Journal of Political Economy 74 (1966) 132-157
89. Lockwood M. Non-compensatory preference structures in non-market valuation of natural area policy. Australian Journal of Agricultural Economics 40 (1996) 85-101
90. Lockwood M. Integrated value assessment using paired comparisons. Ecological Economics 25 (1998) 73-87
91. Lockwood M. Preference structures, property rights, and paired comparisons. Environmental and Resource Economics 13 (1999) 107-122
92. Louviere J.J. Conjoint analysis modelling of stated preferences: a review of theory, methods, recent developments and external validity. Journal of Transportation Economics and Policy 22 1 (1988) 93-119
93. Louviere J.J. Experimental choice analysis: introduction and overview. Journal of Business Research 24 2 (1992) 89-96
94. McFadden D. Rationality for economists?. Journal of Risk and Uncertainty 19 (1999) 73-105
95. McFadden D., and Leonard G.K. Issues in contingent valuation of environmental goods: Methodologies for data collection and analysis. In: Hausman J.A. (Ed). Contingent Valuation: A Critical Assessment (1993), North-Holland/Elsevier Science Publishers, Amsterdam 165-208
96. Milgrom P.R. Is sympathy an economic value? Philosophy, economics, and the contingent valuation method. In: Hausman J.A. (Ed). Contingent Valuation: A Critical Assessment (1993), North-Holland/Elsevier Science Publishers, Amsterdam 417-442
97. Mitchell R.C., and Carson R.T. Using Surveys to Value Public Goods: The Contingent Valuation Method (1989), Resources for The Future, Washington D.C.
98. Morey E.R. Confuser surplus. American Economic Review 74 1 (1984) 163-173
99. Ng Y.-K. From preference to happiness: towards a more complete welfare economics. Social Choice and Welfare 20 2 (2003) 307-350
100. Nyborg K. Homo economicus and homo politicus: interpretation and aggregation of environmental values. Journal of Economic Behavior and Organization 42 (2000) 305-322
101. Payne J.W., Schkade D.A., Desvousges W.H., and Aultman C. Valuation of multiple environmental programs. Journal of Risk and Uncertainty 21 (2000) 95-115
102. Poe G.L., Clark J.E., Rondeau D., and Schulze W.D. Provision point mechanisms and field validity tests of contingent valuation. Environmental and Resource Economics 23 (2002) 105-131
103. Portney P. The contingent valuation debate: Why economists should care. Journal of Economic Perspectives 8 4 (1994) 3-17
104. Randall A., and Hoehn J.P. Embedding in market demand systems. Journal of Environmental Economics and Management 30 (1996) 369-380
105. Randall A., Ives B., and Eastman C. Bidding games for valuation of aesthetic environmental improvements. Journal of Environmental Economics and Management 1 (1974) 132-149
106. Randall A., and Stoll J.R. Consumer's surplus in commodity space. American Economic Review 71 (1980) 449-457
107. Ready R.C., Navrud S., and Dubourg W.R. How do respondents with uncertain willingness to pay answer contingent valuation questions?. Land Economics 77 (2001) 315-326
108. Rondeau D., Schulze W.D., and Poe G.L. Voluntary revelation of the demand for public goods using a provision point mechanism. Journal of Public Economics 72 3 (1999) 455-470
109. Root M. Philosophy of Social Science (1993), Blackwell, Oxford
110. Rose S.K., Clark J., Poe G.L., Rondeau D., and Schulze W.D. Field and laboratory tests of a provision point mechanism. Resource and Energy Economics 24 (2002) 131-155
111. Rosen S. Hedonic prices and implicit markets: product differentiation in pure competition. Journal of Political Economy 82 (1974) 34-55
112. Rossi P.H., Wright J.D., and Anderson A.B. Handbook of Survey Research (1983), Academic Press, New York
113. Sagoff M. Some problems with environmental economics. Environmental Ethics 10 (1988) 55-74
114. Samuelson P. Consumption theory in terms of revealed preference. Economica 15 (1948) 243-253
115. Sen A. Personal utilities and public judgements: or what's wrong with welfare economics. Economic Journal 89 (1979) 537-558
116. Sen A. On Ethics and Economics (1987), Blackwell, Oxford
117. Sen A. The discipline of cost-benefit analysis. Journal of Legal Studies 29 (2000) 931-952
118. Schulze W., McClelland G., Waldman D., and Lazo J. Sources of bias in contingent valuation. In: Bjornstad J., and Kahn J.R. (Eds). The Contingent Valuation of Environmental Resources: Methodological Issues and Research Needs (1996), Brookfield, Vt. Edward Elgar, Cheltenham, UK
119. Seip K., and Strand J. Willingness to pay for environmental goods in Norway: a contingent valuation study with real payments. Environmental and Resource Economics 2 (1992) 91-106
120. Seippel Ø. Political environmentalism: class interestmodern values or postmodern feelings?. ProSus Working Paper 2/98 (1998), ProSus-Program for Research and Documentation for a Sustainable Society, Oslo
121. Shogren J.F., Shin S.Y., Hayes D.J., and Klieberstein J.B. Resolving difference in willingness to pay and willingness to accept. American Economic Review 84 (1994) 255-270
122. Smith V.K. Household production functions and environmental benefit estimation. In: Braden J.B., and Kolstad C.D. (Eds). Measuring the Demand for Environmental Quality (1991), North-Holland/Elsevier Science Publishers, Amsterdam 41-71
123. Smith V.K. Arbitrary values, good causes, and premature verdicts. Journal of Environmental Economics and Management 22 (1992) 71-89
124. Smith V.K. Lightning rods, dart boards, and contingent valuation. Natural Resources Journal 34 1 (1994) 121-152
125. Smith V.K., and Osborne L.L. Do contingent valuation estimates pass a 'scope' test?. Journal of Environmental Economics and Management 31 (1996) 287-301
126. Solow R.M. How did economics get that way and what way did it get?. Daedalus 126 1 (1997) 39-58
127. Spash C.L. Ethical motives and charitable contributions in contingent valuation: empirical evidence from social psychology and economics. Environmental Values 9 (2000) 453-479
128. Spash C.L., and Hanley N. Preferences, information and biodiversity preservation. Ecological Economics 12 (1995) 191-208
129. Stevens T.H., Echeverría J., Glass R.J., Hager T., and More T.A. Measuring the existence value of wildlife: what do CVM estimates really show?. Land Economics 67 4 (1991) 390-400
130. Stigler G.J. The economics of information. Journal of Political Economy 69 3 (1961) 213-225
131. Stigler G.J., and Becker G.S. De Gustibus Non Est Disputandum. Journal of Political Economy 67 2 (1977) 76-90
132. Svedsäter H. Contingent valuation of global environmental resources: test of perfect and regular embedding. Journal of Economic Psychology 21 (2000) 605-623
133. Tallontire, A., Rentsendorj, E., 2000. Consumers and ethical trade: a review of current literature. Draft January 2000. Natural Resources and Ethical Trade, UK.
134. Varian H.R. Revealed preference with a subset of goods. Journal of Economic Theory 46 (1988) 179-185
135. Varian H.R. Microeconomic Analysis. 3rd ed. (1992), Norton and Company Inc., New York
136. Vatn A. Environmental valuation and rationality. Land Economics 80 1 (2004) 1-18
137. Vatn A., and Bromley D.W. Choices without prices without apologies. Journal of Environmental Economics and Management 26 (1994) 129-148
138. Veisten K., Hoen H.F., Navrud S., and Strand J. Scope insensitivity in contingent valuation of complex environmental amenities. Journal of Environmental Management 73 4 (2004) 317-331
139. Veisten K., Hoen H.F., and Strand J. Sequencing and the adding-up property in contingent valuation of endangered species: are contingent non-use values economic values?. Environmental and Resource Economics 29 4 (2004) 419-433
140. Veisten, K., Navrud, S., 2006. Contingent valuation and actual payment: assessing an induced truth-telling mechanism and elicitation formats for voluntary payments and passive-use. Applied Economics, in press.
141. Veisten, K., Navrud, S., Valen, J.S.Y., 2006. Lexicographic preference in biodiversity valuation: tests of inconsistencies and willingness to pay. Journal of Environmental Planning and Management, in press.
142. Vossler C.A., and Kerkvliet J. A criterion validity test of the contingent valuation method: comparing hypothetical and actual voting behavior for a public referendum. Journal of Environmental Economics and Management 45 (2003) 631-649
143. Vossler C.A., Kerkvliet J., Polasky S., and Gainutdinova O. Externally validating contingent valuation: an open-space survey and referendum in Corvallis, Oregon. Journal of Economic Behavior and Organization 51 2 (2003) 261-277
144. Westskog, H., 1996. The use of cost-benefit analysis to decide environmental policy-a dead end? Draft April, 1996. Centre for Development and the Environment, University of Oslo, Oslo, Norway.
145. Willig R.D. Consumer's surplus without apology. American Economic Review 66 (1976) 589-597
146. Willinger M. La méthode d'évaluation contingente: de l'observation à la construction des valeurs de préservation. Natures Sciences Sociétés 4 1 (1996) 6-22