proper risk aversion on introduit et on etudie une condition comportementale significative sur les fonctions d utilite pour les richesses qui signifie qu une loterie indesirable ne peut jamais etre rendue desirable par la presence d une loterie indesirable independante

one switch utility functions and a measure of risk consider the relative attractiveness to a decision maker of two financial gambles as the wealth of that individual varies it may seem reasonable that either one alternative should be preferred for all wealth levels or that there exists a unique critical wealth level at which the decision maker switches from preferring one alternative to the other decreasing risk aversion is not sufficient for this property to hold we identify the small class of utility functions for which it does we show how the property leads naturally to a measure of risk the results of this paper apply equally well to discounting functions for cash flows one switch discount functions permit at most one change in preference between cash flows as all payoffs are deferred in time

standard risk aversion this paper introduces the concept of standard risk aversion a von neumann morgenstern utility function has standard risk aversion if any risk makes a small reduction in wealth more painful in the sense of an increased reduction in expected utility also makes any undesirable independent risk more painful it is shown that given monotonicity and concavity the combination of decreasing absolute risk aversion and decreasing absolute prudence is necessary and sufficient for standard risk aversion standard risk aversion is shown to imply not only pratt and zeckhauser s proper risk aversion individually undesirable independent risks always being jointly undesirable but also that being forced to face an undesirable risk reduces the optimal investment in a risky security with and independent return similar results are established for the effect of broad class of increases in one risk on the desirability of or optimal investment in a second independent risk

estimating willingness to pay from survey data an alternative pre test market evaluation procedure closed ended contingent valuation surveys are used to assess demands in hypothetical markets and recently have been applied widely to the valuation of non market environmental resources this int

comparative reliability of the dichotomous choice and open ended contingent valuation techniques abstract the comparative reliability of dichotomous choice and open ended contingent valuation methods cvm is evaluated by resurvey of the same households 9 months after their original survey test retest correlations on willingness to pay are statistically significant at the 1 level and range from 0 57 for the dichotomous choice cvm to 0 62 for the open ended cvm the test retest correlations were not statistically different between dichotomous choice and open ended cvm a likelihood ratio test for temporal stability of each method s willingness to pay functions indicates stability half of the time for both methods

valuing non market goods using contingent valuation abstract contingent valuation is a technique being developed by economists for the valuation of environmental commodities not traded in markets this paper discusses the major problem areas associated with this method of value estimation these comprise bias strategic hypothetical and design biases the discrepancy between willingness to pay and compensation demanded the aggregation procedure the choice of question format and non use values some evidence from comparative studies is reported and comments made on the accuracy of contingent valuation answers finally the conditions under which contingent valuation seems to operate best are set out

rational escalation of costs by playing a sequence of unfavorable gambles the martingale playing the martingale strategy is an anomaly reverse to that observed in the st petersburg paradox this paper rationalizes the demonstrated irrationality of playing by characterizing necessary and sufficient conditions under which a utility maximizing decision maker would play the strategy an individual willing to play the martingale may not be deterred by a finite cap on wagers individuals will continue with the strategy in the face of mounting consecutive losses which is thus sequentially rational these results give insight into instances of escalating commitment to a losing cause by analyzing one specific instance of such behavior

valuing environmental commodities some recent experiments a general model of consumer behavior is proposed to assess six recent experiments that have attempted to reveal preferences for environmental goals each experiment used a mix of both the techniques and the theory of demand for non market commodities and each was designed to estimate a non market attitude associated with the environment and to analyze potential biases in the techniques the six cases show some consistency in results the linkage within the contingent market between the environmental attribute institutional setting and the bidding instrument must be realistic and accepted by the respondent to avoid biased results possibly the most important result is the replication of results using a traditional property value study and a contingent bidding approach all evidence obtained to date suggests that hedonic studies of property values or wages travel costs and survey techniques all yield values well one order of magnitude in accuracy 41 references 2 tables

information effects in contingent markets information bias in contingent markets is poorly understood in this paper testable hypotheses concerning beneficial contingent market information effects are developed conceptually perspective information and relative expenditure information were expected to increase comprehension and increase bids provision cost information was expected to counteract free riding behavior and also increase bids hypothesis tests using experimental markets suggested that each information type induced small statistically insignificant bid increases however the combined effect of the three information types induced a desirable statistically significant increase in bids this result supports the contention that not all contingent market information effects are biases

interval estimates of non market resource values from referendum contingent valuation surveys contingent valuation methods cvm have attracted considerable attention in recent years as researchers have begun to resort to survey methods to elicit individual values for non market goods such as environmental resources or public goods cummings brookshire and schulze 1986 and mitchell and carson 1989 offer comprehensive assessments of these methods cvm survey questions come in a variety of forms one format which has proven to be popular is called the discrete choice or take it or leave it referendum or closedended question originally implemented in the literature by bishop and heberlein 1979 since respondents find it very difficult to identify precisely their true point value of access to some resource or public good open ended valuation questions can be unreliable or can discourage response in contrast most people are familiar with being confronted by a posted price for a good and with deciding whether or not they would buy at that price this is the strategy behind discrete choice cvm questions a different hypothetical price is offered to each respondent and by their yes no response to the question of whether they would be willing to pay this price the researcher gains information about their true underlying point value one persistent difficulty with the econometric techniques that are currently used most widely to analyze referendum contingent valuation data is the absence of confidence intervals for the ultimate value estimates early empirical applications approximate mean valuations using a truncated mean based on a logit model with the upper limit being the highest bid value in the sample unfortunately the variance of this estimated mean cannot easily be recovered from the numerical integration procedure commonly used to calculate the

experiments on the difference between willingness to pay and willingness to accept comment reply willingness to pay wtp and willingness to accept wta measures of welfare change have been found to differ substantially when elicited from surveys or experimental market transactions conventional economic theory suggests that the difference between wtp and wta should be smaller than those observed in empirical tests this study focuses on the hypothesis that the availability of substitutes for the good being evaluated affects the difference between the two measures the results suggest that the existence of a substitute does reduce the difference between wtp and wta however the difference between these two measures is significant with or without substitutes

repeated optional gambles and risk aversion we analyze in this paper the effect of age on the optimal dynamic strategy toward repeated independent gambles when deciding to accept or to reject a lottery that is offered today the gambler knows how many lotteries can yet be played in the future we first characterize the optimal dynamic strategy when future lotteries are identically distributed we show that the existence of future lotteries always increases the willingness to gamble today when the sequence of lotteries is independent but not identically distributed we show that this does not need to be true this analysis can be applied to the problem of investing in indivisible risky investment projects or to the problem of dynamic optimal insurance demand

prospect theory mental accounting and differences in aggregated and segregated evaluation of lottery portfolios if individuals have to evaluate a sequence of lotteries their judgment is influenced by the presentation mode experimental studies have found significantly higher acceptance rates for a sequence of lotteries if the overall distribution was displayed instead of the set of lotteries itself mental accounting and loss aversion provide an easy and intuitive explanation for this phenomenon in this paper we offer an explanation that incorporates further evaluation concepts of prospect theory our formal analysis of the difference in aggregated and segregated portfolio evaluation demonstrates that the higher attractiveness of the aggregated presentation mode is not a general phenomenon as suggested in the literature but depends on specific parameters of the lotteries the theoretical findings are supported by an experimental study in contrast to the existing evidence and in line with our theoretical results we find for specific types of lotteries an even lower acceptance rate if the overall distribution is displayed

congestion travel cost recreational demand models and benefit evaluation abstract the treatment of congestion in travel cost demand models for recreational sites is a subject of considerable importance for both the allocation and management of public lands in a recent issue of this journal wetzel argued that the use of the travel cost method will always lead to underestimates of the true benefits provided by a site because of the role of congestion the purpose of this paper is to show that his results are misleading it is not possible to derive a priori the direction of the bias in the aggregate demand for a recreational site s services due to congestion in a given season thus wetzel s conclusions on the bias in benefits are misleading the most appropriate treatment of congestion requires that travel cost models be amended to reflect the effects of congestion on a the modeling of individual behavior b the estimation of an individual s demand for a recreational site s service and c the description of how a site s services are allocated across individual users

validation of empirical measures of welfare change a comparison of nonmarket techniques since the passing of the flood control act of 1936 the attention of many resource economists has been directed towards measuring the benefits and costs of alternative uses of natural resources increasingly it has been recognized that the value of some of these uses is not explicitly determined through market transactions this has led to the focus of much attention upon the development of nonmarket methods to estimate the value of these uses in the 1940s the groundwork for the travel cost method was established by hotelling prewitt 1949 following this in the 1960s davis initiated the basic foundation for bidding methods davis 1963 which were later to be subsumed under the heading of contingent valuation methods brookshire randall and stoll 1980 schulze d arge and brookshire 1981 thayer 1981 both of these methods will be further discussed below in addition to these two methods a third approach the unit day value method has been recognized as acceptable but not preferred for the valuation of recreational uses of water and related land resources dwyer kelley and bowes 1977 u s water resources council 1979 given the existence of alternative methods of estimating the value of resource uses several obvious questions arise one of the first of these is under what circumstances is each method most appropriate existing literature has focussed sufficiently on this question and pointed out limitations of each especially the travel cost method and unit day value methods brookshire ives and schulze 1976 dwyer kelly and bowes 1977 freeman 1979 mcconnell 1975 randall ives and eastman 1977 schulze d arge and brook

the value of pre decision side bets for utility maximizers if an alternative is attractive only at certain wealth levels of a decision maker typically above some critical level then there will be occasions when it is better to enter into an independent side bet prior to making a decision than to accept or reject the alternative outright

stated preferences real behaviour and anchoring some empirical evidence we compare different contingent valuation question formats with each other and with observed behaviour for a non monetary estimation task the expected number of kilometers travelled by automobile open ended questions open ended follow up questions dichotomous choice dc questions and double bound dc questions are included the single and double bound dc questions result in an estimated mean about twice as high as the actual value and the open ended mean the dc question overestimation seems to be due to an anchoring effect leading to yea saying behaviour our results about the difference between dc questions and open ended questions is consistent with the pattern observed in contingent valuations studies of the willingness to pay our results indicates that dc questions seem to be associated with a general overestimation problem that is present even for simple non monetary estimation tasks

valuation of ecotourism resources using a contingent valuation method the case of the korean dmz abstract the korean demilitarized zone dmz which has been untouched by human interference for the last half century has become a sanctuary for rare species of animals and plants conflicts concerning development between communities and environmentalists are arising estimates of the preservation value of the dmz are necessary for society to properly address these issues such estimates will help policy makers address issues of conservation management sustainable development and public financial support given this situation the objectives are two fold the primary objective of this study is to obtain estimates of the preservation value of the korean dmz and civilian control zone ccz a secondary objective is to examine the potential for hypothetic bias in respondents answers in a contingent valuation method framework findings suggest hypothetical bias is present in the survey including a real payment vehicle may reduce hypothetical bias in eliciting willingness to pay wtp best estimates are the mean wtp is us 16 74 per capita aggregate preservation value lies between us 264 and 602 million these findings indicate that conservation of the dmz and ccz is not only important for moral and ecological reasons but the dmz and ccz are of considerable economic value to south koreans any development unfriendly to the environment will degrade the quality of the ecosystem of the dmz as well as decrease its economic value

a contextual uncertainty condition for behavior under risk suppose that your choice between uncertain financial prospects is made more difficult by two independent contextual uncertainties concerning the size of your existing wealth one contextual uncertainty has a greater spread than the other if you could resolve one of these contextual uncertainties before making your choice would you rather it be the larger or the smaller in this paper we explore the intuitive notion that it ought to be more advantageous to resolve larger rather than smaller contextual uncertainties the utility function for wealth uw aw be cwa b c 0 is the only utility function that satisfies this condition and that is also increasing and risk averse at all wealth levels

contingent valuation techniques for assessing environmental impacts further evidence abstract this paper provides further evidence on the development and application of the iterative bidding technique used to assess environmental impacts three specific issues the hypothetical nature of the survey technique the questionnaire information structure and the bidding procedure starting point are examined theoretically and empirically to determine their effect on individual bid behavior the empirical results indicate that the importance of these influences may have been overstated in earlier studies

valuing health care using willingness to pay a comparison of the payment card and dichotomous choice methods this paper compares willingness to pay wtp estimates generated from the dichotomous choice dc and payment card pc approaches in a split sample wtp experiment concerned with allocating scarce health care resources across three health care interventions the dc approach is shown consistently to generate larger welfare estimates than the pc observed difference between pc and dc experiments cannot be explained by the inclusion of non demanders or methods of statistical analysis but may be partly explained by yea saying no evidence of range bias or mid point bias was found with pc responses data were also collected on respondents ordinal rankings of the three interventions and person trade offs ptos neither of these approaches converged with wtp future work must address the decision heuristics individuals employ when responding to valuation experiments

welfare measurements using contingent valuation a comparison of techniques three commonly used techniques of asking contingent valuation questions are compared iterative bidding payment cards and dichotomous choice the results reveal that no single contingent valuation technique is neutral in the elicitation of hicksian surplus and each technique has its strengths and weaknesses the iterative bidding estimates contain a starting point bias while the payment card and dichotomous choice estimates were influenced by the interviewers soliciting the contingent values finally the analysis of dichotomous choice responses involves unresolved issues that warrant further investigation on the other hand dichotomous choice is the easiest technique to administer in a survey setting

valuing public goods a comparison of survey and hedonic approaches although the theory of public goods has progressed rapidly since paul samuelson s seminal article the empirical measurement of the value of demand for public goods only recently has received increased attention perhaps the best known and most widely accepted empirical approach has been the use of hedonic prices wherein for example it is assumed that either wages or housing values reflect spatial variation in public good characteristics of different communities this indirect approach based on theoretical work of charles tiebout kelvin lancaster sherwin rosen and others has proven quite successful among public goods or bads which have been valued using the hedonic approach are climate i hoch air pollution robert anderson and thomas crocker d harrison and d rubinfeld social infrastructure r cummings et al and other community characteristics such as noise level j nelson and ethnic composition ann schnare an alternative approach is to directly ask households or individuals to state their willingness to pay for public goods using survey techniques despite arguments that strategic bias will invalidate survey results there exists the need for an alternative to the hedonic approach as an example consider the case of a remote and unique scenic vista valuable to recreators which is threatened by air pollution from a proposed coal fired plant a typical situation in the western united states although it is possible in principle to impute the value of clean air and visibility from the relative decline in local visitation which might follow construction of a power plant information on the value of visibility at the site is needed prior to construction for socially optimal decision making on plant location and pollution control equipment the hedonic approach is unavailable both because the scarcity of local population as opposed to recreators makes use of wage or property value data impossible and because scenic vistas may themselves be unique for these reasons a randall et al first applied survey methods for valuing visibility and other environmental effects of large coal fired power plants in the four corners region of new mexico since this initial application the survey approach has been widely used to value environmental commodities where market data for hedonic analysis is difficult to acquire see for example brookshire ives and schulze rowe et al brookshire et al other early attempts to value public goods using the survey approach include r davis peter bohm and j hammack and g brown although results of using the survey approach for estimating the value of public goods appear to be internally consistent replicable and consistent with demand theory see schulze et al little work on external validation has been reported thus the purpose of this paper is to report on an experiment designed to validate the survey approach by direct comparison to a hedonic property value study the los angeles metropolitan area was chosen for the experiment because of the well defined air pollution problem and be assistant professor university of wyoming assistant professor university of missouri rolla associate professor university of wyoming and professor university of wyoming respectively the research reported here was funded under a grant methods development for assessing air pollution control benefits from the u s environmental protection agency we would like to give special thanks to alan carlin and shelby gerking for their helpful suggestions and contributions additional helpful comments were received from a myrick freeman iii john tschirhart and james murdoch all conclusions are of course our sole responsibility

consumer s surplus without apology the purpose of this paper is to settle the controversy surrounding consumer s surplus and by so doing to validate its use as a tool of welfare economics i will show that observed consumer s surplus can be rigorously utilized to estimate the unobservable compensating and equivalent variations the correct theoretical measures of the welfare impact of changes in prices and income on an individual i derive precise upper and lower bounds on the percentage errors of approximating the compensating and equivalent variations with consumer s surplus these bounds can be explicitly calculated from observable demand data and it is clear that in most applications the error of approximation will be very small in fact the error will often be overshadowed by the errors involved in estimating the demand curve the results in no way depend upon arguments about the constancy of the marginal utility of income consequently this paper supplies specific empirical criteria which can replace the apologetic caveats frequently employed by those who presently apply consumer s surplus moreover the results imply that consumer s surplus is usually a very good approximation to the appropriate welfare measures to preview below i establish the validity of these rules of thumb for a

differences between willingness to pay estimates from open ended and discrete choice contingent valuation methods the effects of heteroscedasticity most comparative studies find that the discrete choice contingent valuation method dc cvm yields higher willingness to pay wtp estimates than the open ended oe format in this paper we discuss and test several hypotheses to explain why wtp estimates from oe and dc cvm questions differ we find that wtp estimates from discrete choice data are very sensitive to assumptions made about the random utility in particular violation of the homoscedasticity assumption may lead to biased wtp estimates if the error terms are correlated with the cost this violation was a main source of difference in wtp estimates in our studies

changes in background risk and risk taking behaviour economic decision making under uncertainty often takes place in the presence of multiple risks and in markets that are less than complete as a consequence choices about endogenous risks sometimes must be made while simultaneously facing one or more immutable exogenous background risks that are not under the control of the agent and that are independent of endogenous risks it is somehow natural to assume that an exogenous deterioration in background wealth will cause an individual to take more care elsewhere if we define a deterioration for example as making the individual poorer by removing a fixed amount of initial wealth we know from pratt 1964 that decreasing absolute risk aversion dara of an individual s von neumann morgenstern utility function yields this natural result if on the other hand background wealth becomes riskier due to the addition of a zero mean risk that is also statistically independent of all other risks behavior will be more risk averse if and only if preferences are risk vulnerable as defined by gollier and pratt 1996 risk vulnerability described below in section 4 is a stronger notion than dara and includes proper risk aversion pratt and zeckhauser 1987 and standard risk aversion eeckhoudt and kimball 1992 kimball 1993 as particular cases but a deterioration in background wealth may encompass more complicated distribution changes than the introduction of another statistically independent risk in this paper we examine background wealth deteriorations that take the form of both general firstand second degree stochastic dominance changes in risk fsd and ssd respectively in particular we determine conditions that are both necessary and sufficient for each of these two types of background risk changes to imply more risk averse behavior on the part of the individual for the case of fsd changes this condition turns out to be ross stronger characterization of decreasing absolute risk aversion in the case of general ssd changes in the distribution of background wealth the condition derived is a stronger version in ross sense of the conditions characterizing preferences that are locally risk vulnerable in the sense of gollier and pratt the necessary and sufficient conditions derived are fairly restrictive upon preferences however if we take as positive behavior that individuals act in a more risk averse manner whenever the distribution of background wealth deteriorates these conditions place canonical limits upon appropriate utility representations at the very least they

efficient estimation methods for closed ended contingent valuation surveys closed ended contingent valuation surveys can be very useful in the evaluation of nonmarket resources respondents merely state whether they would accept or reject a hypothetical threshold amount either as payment for giving up access to the resource or as a fee for its use the authors develop a maximum likelihood procedure which exploits the variation in the threshold values to allow direct and separate point estimates of regression like slope coefficients and error standard deviations without truncation bias their illustration uses data from a survey of recreational fisherman to examine factors which influence individuals willingness to pay copyright 1987 by mit press

investment flexibility and the acceptance of risk abstract the hypothesis examined in this paper is that the greater the investor s flexibility the easier it is for him to change his portfolio depending on his results the more willing he will be to accept risks when the investor has no control on the size of the risky investment but can choose between one risky and one riskless asset this conjecture is shown to be correct however if there is more than one risky asset each period counterexamples demonstrate that flexibility rarely ensures greater risk taking for the standard portfolio problem in which investors are free to determine the size of their investment in a risky asset flexibility always raises the demand for the risky asset if constant relative risk aversion is less than unity but counterexamples can always be found when the constant relative risk aversion is larger than unity journal of economic literatureclassification numbers g11 d81 d84

some issues in the application of closed ended willingness to pay studies to valuing health goods an application to antenatal care in scotland limited resources coupled with unlimited demands means that decisions have to be made concerning the allocation of scarce health care resources the economic instrument of willingness to pay wtp is one instrument that can be used to help this decision making process recommendations from the environmental economics literature suggest that the closed end ce wtp approach should be used this approach is just beginning to be used to value health goods this paper addresses the sensitivity of the closed ended wtp approach to three issues the design of the bid vector the upper and lower limits of integration and the method of analysis these are discussed with reference to a study looking at the value of alternative models of ante natal care in scotland the results are discussed and conclusions made concerning the use of the ce wtp instrument for valuing health goods

consistency between contingent valuation estimates a comparison of two studies of uk national parks bateman i willis k and garrod g 1994 consistency between contingent valuation estimates a comparison of two studies of uk national parks reg studies 28 457 474 recent years have seen a significant increase in the application of the contingent valuation method to the evaluation of environmental preferences in the uk recent theoretical and methodological developments suggest that this increase is likely to be sustained for the foreseeable future this paper examines the issue of consistency across studies carried out to date in the uk attention is initially focused upon two major studies which allow the comparison of a number of findings analysis is then extended to a large number of smaller studies these comparisons suggest that the results obtained to date are both consistent and logically ordered with reference to the environmental good and the change in provision under consideration across studies bateman i willis k et garrod g 1994 la coherence des estimations contingentes une

measuring the cost of time in recreation demand analysis an application to sportfishing since the work of cesario and knetsch economists have recognized that the opportunity cost of time plays an important role in determining the demand for outdoor recreation the opportunities one has for spare time are more significant for consumption of time intensive outdoor recreation activities than for other commodities especially nondurables bishop and heberlein illustrate the overwhelming importance of time costs to final recreational values total consumer surplus is nearly four times as large when time costs are added at half the income rate as when time costs were set at zero p 21 despite the recognition economists have neither successfully integrated the costs of time with the methods of recreational demand analysis nor reached a consensus on how it should be measured brown charbonneau and hay state finally the apparently crucial importance of how opportunity cost of time is handled needs further work while we are convinced it is an appropriate concept exactly how it should be included and measured s remains to be determined p 24 several approaches have been taken to include it in the travel cost method one approach brown and nawas gum and martin suggests that time in transit be considered as a separate independent variable another approach bishop and heberlein brown charbonneau hay nicols bowes dwyer cesario and knetsch measures the cost of time and adds it to other costs several approaches have been suggested to measure time costs one approach is simply to choose an hourly wage e g 2 00 per hour or perhaps the minimum wage rate a more flexible but still ad hoc approach is to use some proportion of the individual s wage rate as the opportunity cost of time nichols bowes dwyer the proportion is usually taken from independent studies and used to value the travel time this approach is better than using a constant opportunity cost of time because it allows variation across individuals it suffers because the choice of the percentage of the wage rate is arbitrary independent of the sampled population cesario has discussed the consequences of ignoring time costs and the differences in values arising from alternative measurement approaches in this paper we argue that the opportunity cost of time is some proportion of the individual s market wage rate or income per hour and that this proportion can be determined from sample data this method permits the proportion to vary from one study to another rather than imposing either an arbitrary estimate or one from a sample different from the study s sample

protest responses in contingent valuation a significant number of respondents to contingent valuation surveys tend to either state a zero bid or refuse to state a bid at all for reasons associated with the process of valuation these protest responses are routinely removed from contingent valuation samples because it is assumed that they are not indicative of respondents true values the censoring of protest responses has led to the emergence of a definitional controversy one view is that the definition of protest responses and the rules for censoring them are dependent on whether the practitioner conceives of the contingent valuation survey as a market or as a referendum however what is not acknowledged is the possibility that protest responses and their meaning may vary according to the type of good being valued the elicitation format and the interaction between these elements and external factors this potential renders the development of unambiguous rules for censoring protest responses difficult moreover when willingness to pay is viewed as a behavioural intention it becomes important to determine what the responses actually mean this approach does not assume an interpretative position a priori against which the responses should be judged but seeks to inform an existing understanding which is inadequate

valuing public goods discrete versus continuous contingent valuation responses independent applications of open ended and dichotomous choice formats are compared using tests of means estimating joint likelihood functions and nonparametric tests of distributions the null hypothesis of no difference in the open ended and dichotomous choice estimates of central tendency cannot be rejected for two out of three data sets while estimated standard deviations are significantly different for all three data sets in addition actual dichotomous choice means and standard deviations exceed those from comparable synthetic dichotomous choice data sets suggesting either open ended questions underestimate values or dichotomous choice bid structures may lead to systematic overestimates

referendum models and economic values theoretical intuitive and practical bounds on willingness to pay innovations in the estimation of referendum type contingent valuation models have led to willingness to pay wtp measures inconsistent with consumer preferences and unbounded from above or below we propose a set of criteria which guarantee a bounded measure of wtp the criteria reject the traditional random utility model with unrestricted error terms in favor of the random wtp model with bounds on wtp once wtp is bounded by zero and income the form of the distribution is less consequential a new model for wtp is developed based on the beta distribution and is compared to previously estimated models

statistical approaches to the fat tail problem for dichotomous choice contingent valuation if a cumulative density function esti mated from dichotomous choice data has an unre alistically fat right hand tail mean willingness to pay wtp will be overestimated truncating the range of integration results in a lower bound esti mate of the true mean wtp a normalization pro cedure proposed by boyle welsh and bishop 1988 unnecessarily depresses the estimate further a new statistical approach is presented that allows a best guess estimate of mean wtp because this estimate involves extrapolation beyond the range of the data it tends to be highly variable jel q21

individual travel cost method estimation and benefit assessment with a discrete and possibly grouped dependent variable the trip visit variable in the individual travel cost method is often regarded as discrete furthermore it is often reported in surveys as a grouped variable the number of visits reported falling into one of several classes this paper develops a travel cost model which takes account of discreteness and grouping in both demand and benefit estimation a case study and associated simulations are then reported which indicate the potential extent of bias that may arise from ignoring discreteness grouping in demand and benefit estimation the information loss involved in varying the size of visit classes is also examined

measuring the existence value of wildlife what do cvm estimates really show two research programs are brought together to contribute to the growing body of work on alternatives to standard welfare based approaches to environmental valuation and policy the first is the theoretical literature undermining the new welfare

asymmetric cost sharing mechanisms we describe the construction and analysis of asymmetric cost sharing mechanisms in which a variety of axioms are applied to subsets of the agents goods we show that the analysis can be quite subtle as apparently similar axiomatizations lead to significantly different results in particular combinations of symmetric mechanisms can be extremely asymmetric and biased in addition we characterize some interesting mixed mechanisms