generalized travel cost model and water quality benefits a reconsideration with federal agencies required to conduct benefit cost analyses for each new major regulation analyses of water quality changes are likely to be an increasingly important part of the policymaking process a revised version of the travel cost demand model and illustrations show the importance of these revisions for the model s estimates although the magnitude of the difference in benefit estimates between the original and new versions of the model varies with the specific recreation site selected the findings indicate that the original model generally implied estimated benefits from three to over 30 times as large as the revised model this implies that judgment can play an important role in the definition and use of economic models as well as the need for better information on households recreation decisions and more complete description of recreation site characteristics 15 references 4 tables

a hedonic travel cost analysis for valuation of multiple components of site quality the recreation value of forest management abstract one benefit of managing forests is that one can alter the qualities of sites the value of changing site qualities however is generally not known this paper develops a formal hedonic travel cost model which can be used to estimate the value of both marginal and non marginal changes to sites the approach accommodates multiple simultaneous changes in site characteristics estimating this model using a set of permits from wilderness areas leads to revealed preference estimates of the recreational value of clear cuts old growth and nine other wilderness attributes

household labor market choices and the demand for recreation this paper introduces household labor market choices into the demand for recre ation showing that the opportunity cost of time wage rate connection is severed when several household members have the opportunity to par ticipate in the labor market at fixed wages an ap plication of recreation demand for households in new bedford massachusetts shows that the rec reation demand models and estimates of con sumer surplus are sensitive to household labor market choices q26

do big countries win tariff wars yes it is widely believed that tariffs invite retaliation and that the postretaliation equilibrium l eaves all countries worse off than they would be at free trade the a uthors present a simple pure exchange model with two countries and t wo goods and show which endowment patterns are consistent with this belief they find that if one country is substantially bigger than th e other it can expect to gain from a tariff war despite retaliation the model can be extended to show that the advantage obtained by bei ng part of a large trading unit can help explain the formation of cus toms unions copyright 1988 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

impulse control of pension fund contributions in a regime switching economy abstract in defined benefit pension plans allowances are independent from the financial performance of the fund and the sponsoring firm pays regularly contributions to limit deviations of fund assets from the mathematical reserve necessary for covering the promised liabilities this research paper proposes a method to optimize the timing and size of contributions in a regime switching economy the model takes into consideration important market frictions like transactions costs late payments and illiquidity the problem is solved numerically using dynamic programming and impulse control techniques our approach is based on parallel grids with trinomial links discretizing the asset return in each economic regime

regime switching in the relationship between equity returns and short term interest rates in the uk abstract this paper examines the relationship between uk equity returns and short term interest rates using a two regime markov switching egarch model the results suggest one high return low variance regime within which the conditional variance of equity returns responds persistently but symmetrically to equity return innovations in the other low mean high variance regime equity volatility responds asymmetrically and without persistence to shocks to equity returns there is evidence of a regime dependent relationship between shorter maturity interest rate differentials and equity return volatility furthermore there is evidence that events in the money markets influence the probability of transition across regimes

revealing preferences for leisure time from stated preference data when consumer choice is constrained by time as well as money willingness to pay can be defined with respect to either numeraire the two measures can be related formally within a utility consistent model of choice subject to two constraints furthermore when information is collected on both the respondent s marginal value of time can be identified a system of willingness to pay time and money and the marginal value of leisure time is estimated jointly in an application to california whalewatching and whale stock enhancement the empirical approach can be applied with only minor additions to survey techniques for nonmarket valuation

using revealed preferences to estimate the value of travel time to recreation sites the opportunity value of travel time vtt is one of the most important elements of the total cost of recreation day trips and arguably the most difficult to estimate most studies build upon the theoretical framework proposed by becker 1965 by using a combination of revealed and stated preference data to estimate a value of time which is uniform in all activities and under all circumstances this restriction is relaxed by deserpa s 1971 model which allows the value of saving time to be activity specific we present the first analysis which uses actual driving choices between open access and toll roads to estimate a vtt specific for recreation trips thereby providing a value which conforms to both becker s and deserpa s theoretical models using these findings we conduct a monte carlo simulation to identify generalizable results for subsequent valuation studies our results indicate that 3 4 of the wage rate provides a reasonable approximation of the average vtt for recreation trips while the commonly implemented assumption of 1 3 of the wage rate generates downward biased results

arming in the global economy the importance of trade with enemies and friends abstract we analyze how trade openness matters for interstate conflict over productive resources our analysis features a terms of trade channel that makes security policies trade regime dependent specifically trade between two adversaries reduces each one s incentive to arm given the opponent s arming if these countries have a sufficiently similar mix of initial resource endowments greater trade openness brings with it a reduction in resources diverted to conflict and thus wasted as well as the familiar gains from trade although a move to trade can otherwise induce greater arming by one country and thus need not be welfare improving for both aggregate arming falls by contrast when the two adversaries do not trade with each other but instead trade with a third friendly country a move from autarky to trade intensifies conflict between the two adversaries inducing greater arming with data from the years surrounding the end of the cold war we exploit the contrasting implications of trade costs between enemies versus trade costs between friends to provide some suggestive evidence in support of the theory

the opportunity cost of travel time in recreation demand models deciding how to allocate forage among animals is a fundamentally important process in range management the wisdom of these decisions can be enhanced by estimating the marginal value of forage needed by competing species we present a method for

mean variance portfolio and contribution selection in stochastic pension funding abstract in this paper we study the problem of simultaneous minimization of risks and maximization of the terminal value of expected funds assets in a stochastic defined benefit aggregated pension plan the risks considered are the solvency risk measured as the variance of the terminal fund s level and the contribution risk in the form of a running cost associated to deviations from the evolution of the stochastic normal cost the problem is formulated as a bi objective stochastic problem of mean variance and it is solved with dynamic programming techniques we find the efficient frontier and we show that the optimal portfolio depends linearly on the supplementary cost of the fund plus an additional term due to the random evolution of benefits

optimal transition to renewable energy with threshold of irreversible pollution when cheap fossil energy is polluting and pollutant no longer absorbed beyond a certain concentration there is a moment when the introduction of a cleaner renewable energy although onerous is optimal with respect to inter temporal utility the cleaner technology is adopted either instantaneously or gradually at a controlled rate the problem of optimum under viability constraints is 6 dimensional under a continuous discrete dynamic controlled by energy consumption and investment into production of renewable energy viable optima are obtained either with gradual or with instantaneous adoption a longer time horizon increases the probability of adoption of renewable energy and the time for starting this adoption it also increases maximal utility and the probability to cross the threshold of irreversible pollution exploiting a renewable energy starts sooner when adoption is gradual rather than instantaneous the shorter the period remaining after adoption until the time horizon the higher the investment into renewable energy

the role of site and job characteristics in hedonic wage models recent economic analyses of wage rate differentials have generally used some form of hedonic framework in explaining the observed wage structure while these studies have adopted this common theoretical justification the models have been used to serve two distinct objectives the first of these is an empirical test of the theory of equalizing differences originally introduced by adam smith in such applications see brown 7 lucas 26 olson 28 thaler and rosen 36 and viscusi 40 as examples specific job characteristics measured with technical information or with worker perceptions have been used to explain differences in wage rates across individuals and jobs while there are a number of these studies there has not been a consistent pattern of support for the theory indeed with the exception of job risks many characteristics that a priori would be expected to lead to equalizing differences have often exhibited incorrect and or statistically insignificant measured effects on wages the second use for wage models has been as the basis for an index of the quality of life in urban areas in this framework households are assumed to select residential locations so as to maximize their individual welfare migration between cities provides the mechanism for an equilibrium household assignment under ideal conditions the pattern of equilibrium wage rates reflects the attributes of the cities involved see hoch 20 izraeli 23 cropper lo cropper and arriaga salinas 111 and rosen 31 as examples the purpose of this paper is to develop a model for wage rate differentials that includes both job and site characteristics and to estimate the model with a large micro data set our wage models provide estimates of a market clearing envelope which includes each of two types of past analyses as a

signals or noise explaining the variation in recreation benefit estimates this paper uses meta analysis to summarize the benefit estimates derived from travel cost recreation demand models after reviewing approximately 200 published and unpublished studies prepared from 1970 to 1986 77 were found to report either consumer surplus estimates or sufficient information to derive them using these estimates of the consumer surplus per unit of use from each study it was possible to evaluate the influence of variables describing the site characteristics the activities undertaken at each site the behavioral assumptions and the specification decisions the findings provide clear support for using econometric methods to summarize results from diverse empirical studies they highlight the important research issues in model development and offer a consistency check to the procedures used in benefit transfer analyses for policy evaluations

political limits to globalization we live in an unprecedented age of globalization where technology ideas factors of production and goods are increasingly mobile across national boundaries the current wave of globalization is distinguished from previous ones in part because of the major role of infor mation technology nevertheless globalization is not irreversible openness to international trade finance and technology is a choice that countries make and despite the facilitating role of information technology many countries even many leading players in the world econ omy including the united states china india brazil and russia could decide to close their borders a major cause of the end of the previ ous also historically unprecedented nineteenth century wave of globalization was disillusion ment with the international economic order in

separability and the shadow value of leisure time recreation choices are often viewed as short run decisions conditioned on longer run labor supply using weak separability to reflect this relationship the wage rate is the shadow value of time for individuals who get no utility from work whether or not they are observed to be trading time for money in the short run this result widens the circumstances under which the wage rate not some fraction thereof is the theoretically correct shadow value of time modifications to such a conclusion are developed for cases in which work is a source of utility and in which the first stage choice is not continuous

the hedonic travel cost model a view from the trenches accessible to them consequently it is reasonable to expect that economic models of these decisions will recognize the role of recreation sites characteristics for individual demands and that they will allow for the possibility that the individual s optimal choices may not involve interior solutions in all the available recreation sites in response to these expectations the recent literature has seen a number of innovations in recreation demand models one of these models is based on a fundamen

recreation demand choices and revealed values of leisure time i introduction at least since the work of becker 1965 it has been recognized widely that time may play an important role in consumer demand one of the areas where this may be most significant empirically is in the valuation of natural resource amenities through their associated recreation demands a principal reason is that recreation is a time intensive commodity so that the value of the time spent in recreation would be expected to play a large role in its overall value the potential bias to consumer s surplus estimates of the net economic value of recreation from excluding time prices from the demand model has been recognized from the outset for example by knetsch 1963 and clawson 1959 to incorporate time into recreation demand models researchers have generally adopted the practice suggested by mcconnell 1975 of defining the full price of recreation as the money cost of a trip plus its monetized time cost though the use of full budgets also called for by the becker approach is less widespread bockstael et al 1987 pointed out quite clearly that both full budgets and full prices are required in the demand function if the recreationist is jointly choosing labor supply with recreation at an exogenous marginal wage but that the structure of demand was unclear if the individual was not making such marginal labor supply choices i e if he or she was working fixed hours subsequently larson and shaikh 2001 showed that the full prices full budgets specification is sufficient to satisfy the constraints on demand parameters that arise because choice is made subject to two binding constraints regardless of the individual s position in the labor market they also pointed out that models that use full prices but only money income in effect ignoring the role of time as a resource constraint cannot be consistent with the requirements of choice subject to two constraints although the outlines of how time should enter the structure of demand are becoming clear a major unresolved issue is how to determine its value in practice several studies have followed the basic logic of becker s early work assuming that the opportunity cost of recreation time i e the value of other time forgone in favor of recreation is an exogenous parameter such as the average wage rate or more commonly some fraction thereof this fraction is either chosen arbitrarily or estimated as part of the recreation demand model as in cesario 1976 mcconnell and strand 1981 and smith et al 1983 such assumptions may be erroneous for a variety of reasons assuming the average wage is the appropriate opportunity cost of time presumes that the individual faces no constraints on hours worked derives no utility or disutility from work and has a linear wage function as has been noted by chiswick 1967 bockstael et al 1987 and smith et al 1983 this is unlikely to be true for many people assuming some constant fraction of the wage is the opportunity cost of time especially an arbitrarily chosen fraction also seems likely to be incorrect for most people for all of these reasons an individual s average wage does not necessarily reveal anything about the shadow value of discretionary leisure time either as an upper or lower bound in a recent advance feather and shaw 2000 adapted the heckman 1974 labor supply model to include information supplied by recreationists about their labor supply status in particular whether they felt under or over employed relative to their desired number of hours this information is used to identify subgroups in the data for which the shadow value of leisure time is less than the wage or more than the wage which helps in the estimation of both a wage function and a shadow value of leisure time function this approach produces individual specific estimates of the opportunity cost of leisure time based on their demographics and labor market decisions which are used in a subsequent recreation demand analysis

comparing bargaining solutions in the shadow of conflict how norms against threats can have real effects abstract in many economic environments agents make costly and irreversible investments in guns that may enhance their respective threat payoffs but also shrink the utility possibilities set in such settings with variable threats and a variable utility possibilities set it becomes possible to rank different bargaining solutions in terms of efficiency we compare bargaining solutions within a class in which the influence of the threat point on the bargaining outcome varies across solutions under symmetry we find that the solution in which the threat point is least influential the equal sacrifice solution pareto dominates the other solutions since the equal sacrifice solution puts the least weight on the threat point norms against threats that can be seen in many seemingly rhetorical pronouncements in adversarial relations can mitigate some of the costs of conflict and therefore have efficiency enhancing effects journal of economic literature classification numbers c72 c78 d30 d70 d72 k42

equilibrium strategies in a defined benefit pension plan game abstract we study the optimal management of an aggregated overfunded pension plan of defined benefit type as a two player noncooperative differential game the model s key fact is to consider the fund surplus as a strategic variable that makes the pension plan more attractive both for current and future participants we let the worker participants to act collectively as a single player that claims a share of the surplus and let the sponsoring firm act as the player that cares about the investment of the surplus fund assets the union s objective is to maximize the expected discounted utility of the extra benefits claimed we solve this asymmetric game under two different assumptions on the preferences of the firm in the first scenario the firm aims to maximize expected discounted utility derived from fund surplus while in the second scenario the firm cares about minimizing the probability that the fund surplus reaches very low values

time is money improved valuation of time and transportation costs the proper valuation of time isimportant for estimating the demand for severaleconomic goods this paper explores the propervaluation of time when estimating recreationaldemand where time costs represent asubstantial portion of the purchase price toestimate demand this paper uses a travel costframework to analyze actual behavior revealedpreference data and hypothetical behavior stated preference data which is induced byhypothetical increases in access fees traveltime and travel distance by comparing theresponses to these three contingencies theanalysis adjusts and improves the valuation oftime costs as evidence of this improvement this analysis demonstrates a great increase inthe consistency between the revealed and stateddata similarly this paper improves thevaluation of transportation related costs

valuation optimal asset allocation and retirement incentives of pension plans we provide a framework in which we link the valuation and asset allocation policies of defined benefits plans with the lifetime marginal productivity schedule of the worker and the pension plan formula in turn we examine the retirement policies that are implied by the primitives of the model and the value of pension obligations our model provides an explicit valuation formula for a stylized defined benefits plan the optimal asset allocation policies consist of the replicating portfolio of the pension liabilities and the growth optimum portfolio independent of the pension liabilities we show that the worker will retire when the ratio of pension benefits to current wages reaches a critical value which depends on the parameters of the pension plan and the discount rate using numerical techniques we analyze the feedback effect of retirement policies on the valuation of plans and on the asset allocation decisions article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

selection and recreation demand increased use of on site and user group surveys to estimate travel cost demand models e g caulkins bishop and bowes smith and desvousges has raised inevitable questions about the significance of relying on demand estimates derived solely from surveys of users many of the questions relate to selection effects that is the potential for specification errors and bias caused by an inability to reflect the decisions of nonusers with these types of surveys this issue has received some attention in the recreation literature brown et al bockstael and mcconnell but specific empirical evidence on the implications of alternative approaches for estimating demand models from on site surveys does not exist this article reports the first such evidence using a data set based on a general population sample to compare five methods for estimating travel cost demand models with microdata the findings suggest that the differences in the demand and in the benefit estimates raised by treating the problem using models with either single heckman or double selection catsiapis and robinson ham poirier effects are small however the effects of using alternative estimators for site demands are not these findings are limited because they apply to only one site nonetheless they do highlight the importance of the assumptions used to consider the behavior of nonusers consequently they provide direct motivation for more detailed conceptual and empirical work on the choice processes underlying recreation decisions

searching for the opportunity cost of an individual s time a traditional assumption made in the literature is that the value of an individual s time spent in any activity is equal to his or her wage rate this result stems from the derivation of the value of leisure time in the context of the standard labor supply model this paper pre sents some reasons why the relationship be tween the wage rate and the value of time does not hold suggestions for what to do when the relationship breaks down and the investigator needs some value to impute to the individual are given in the final section of the paper

estimating recreation preferences using hedonic travel cost and random utility models over the last decade several authors have questioned the validity of the hedonic travel cost model arguing instead that the random utility model is a superior method for valuing recrea tional site attributes this paper demonstrates that the two methods emanate from a similar utility theoretic framework yet in practice these methods differ in the assumptions made in their appli cation constraining the underlying utility functions to be consistent both models are applied to the valuation of recreational site attributes in the southeastern united states the way in which each method estimates preferences for site attributes is shown to depend critically on the method and the functional form of the underlying utility function micro economic theory began as an attempt to describe predict and value the demand and supply of consumption goods quality was largely ignored in initial theoretical treatises goods were assumed to be homogeneous over the last two decades however economists have started to address quality within the theory of demand environmental economists have extended the theory further to value the quality of recreational sites an important component of land management two distinct approaches for incorporating quality into recreational analyses have emerged the hedonic travel cost method htc and the discrete choice random utility methods rum the hedonic method views site attributes as though they were individual goods which are bundled together in a single purchase the random utility model treats quality as an index which is estimated by examining a discrete choice of alternative sites facing a consumer because the mathematical derivations for the hedonic rosen 1974 and random utility models mcfadden 1978 are quite different many practitioners do not recognize that both models are based on a common utility theoretic foundation in the first section of this paper we show how the hedonic and random utility methods are consistent with the same utility framework

theory and estimation of the household production function for wildlife recreation abstract the household production function is an intuitively appealing way to model man s interaction with nature this paper models the interaction between the household s behavior and publicly provided inputs into wildlife recreation the paper shows how to compute benefits assuming that the household production function is known the household production function approach collapses to the simple travel cost approach when households are unable to substitute their own inputs for publicly provided inputs in addition the paper demonstrates the conditions under which the parameters of cost and preference functions can be identified the conditions for identification are quite restrictive when several choices are endogenous

trade and insecure resources we construct a model of conflict and trade to study the consequences of interstate disputes over contested resources land oil water or other resources for arming welfare and trade flows different trade regimes imply different costs of such disputes in terms of arming depending on world prices free trade can intensify arming to such an extent that the additional security costs it brings swamp the traditional gains from trade and thus render autarky more desirable for one or all rival states free trade though is always an equilibrium and sometimes is a dominant one with features of a prisoner s dilemma outcome furthermore contestation of resources can reverse a country s apparent comparative advantage relative to its comparative advantage in the absence of conflict and where such conflict is present comparisons of autarkic prices to world prices could be inaccurate predictors of trade patterns

collateral damage trade disruption and the economic impact of war abstract conventional wisdom in economic history suggests that conflict between countries can be enormously disruptive of economic activity especially international trade we study the effects of war on bilateral trade with available data extending back to 1870 using the gravity model we estimate the contemporaneous and lagged effects of wars on the trade of belligerent nations and neutrals controlling for other determinants of trade as well as the possible effects of reverse causality we find large and persistent impacts of wars on trade national income and global economic welfare we also conduct a general equilibrium comparative statics exercise that indicates costs associated with lost trade might be at least as large as the conventionally measured direct costs of war such as lost human capital as illustrated by case studies of world wars i and ii

make trade not war this paper analyses theoretically and empirically the relationship between military conflicts and trade we show that the conventional wisdom that trade promotes peace is only partially true even in a model where trade is economically beneficial military conflicts reduce trade and leaders are rational when war can occur because of the presence of asymmetric information the probability of escalation is lower for countries that trade more bilaterally because of the opportunity cost associated with the loss of trade gains however countries more open to global trade have a higher probability of war because multilateral trade openness decreases bilateral dependence to any given country and the cost of a bilateral conflict we test our predictions on a large data set of military conflicts on the 1950 2000 period using different strategies to solve the endogeneity issues including instrumental variables we find robust evidence for the contrasting effects of bilateral and multilateral trade openness for proximate countries we find that trade has had a surprisingly large effect on their probability of military conflict

stochastic pension funding when the benefit and the risky asset follow jump diffusion processes we study the asset allocation of defined benefit pension plans of the type designed and sponsored by firms with the aim of providing a lifetime pension to the employees at the age of retirement benefits are stochastic combining poisson jumps with brownian uncertainty the sponsor dynamically forms portfolios where the risky asset is also subjected to poisson jumps and brownian uncertainty possibly correlated with the evolution of benefits the objective is to assure future benefits while controlling the contribution made to the fund reserves the problem is solved analytically using dynamic programming techniques

guns butter and openness on the relationship between security and trade sovereign states arm to defend real or hypothetical interests presumably because they cannot engage in complete long term contracting that would prevent such arming international trade therefore takes place within an essentially anarchic context and we can expect trade regimes and security policies to be related indeed many embargoes sanctions and various other forms of trade restrictions that have been used throughout history and continue to be used today can be considered extensions of security policies whereas some security policies can be attributed to trade policy the relationship between trade and security however has been barely explored within economics we could fairly characterize the prevailing view within the discipline as the classical liberal view according to which the expansion of international trade does not just increase the welfare of the trading partners but can also patch up any differences they might have over other contentious issues solomon polachek 1980 represents a rare articulation of this widely held perspective more boldly it could be argued that the expansion of trade always alleviates conflict by forcing the adoption of measures that manage conflict nevertheless one does not need to dig much into history to show that while trade and economic interdependence can contribute to the peaceful resolution of disputes they are not sufficient by themselves to guarantee the absence of war and the reduction of arming many observers before world war i for example considered that the hitherto unprecedented expansion of trade and interdependence between britain and germany made war unthinkable and impossible yet war occurred and with much ferocity and destruction furthermore as donald kagan 1995 pp 373 80 has argued the british policy of appeasement toward germany during the 1930 s was based on similar arguments about the use of economic caltots to avoid war what can inter

insecure resources bilateral trade and endogenous predation a game theoretic analysis of conflict and trade this article analyzes how interstate conflict over resources affects the incentives to trade and how greater trade openness affects the endogenous decisions of arming by enemy countries we identify conditions under which there is trade between two adversary countries and show that each adversary s arming affects domestic welfare in three different ways the first is an export revenue effect which increases welfare because arming causes export revenue to go up i e there is an arming induced terms of trade improvement the second is a resource predation effect which increases welfare because arming increases the appropriation of a rival country s resource input to produce a consumption good the third is an output distortion effect which reduces welfare because arming lowers the domestic production of civilian goods based on these effects we show circumstances in which greater trade openness reduces the intensity of arming we also discuss the implications of resource security asymmetry for conflict and trade

modeling recreation demand within a random utility framework abstract this paper develops a single site single trip random utility model for describing recreation behavior the model is applied to a 1981 survey of households in the pennsylvania monongahela river basin hicksian benefit estimates derived from it are compared with those from a more conventional travel cost model estimated from the same survey

optimum tariffs and retaliation revisited how country size matters in his seminal work on tariff retaliation johnson review of economic studies 21 1953 1954 showed that a country will win a bilateral tariff war if its relative monopoly monopsony power in world trade is sufficiently large however it is unclear from johnson s analysis and from subsequent research on the subject how this power is determined in general economic environments an important goal of this paper is to address this issue with the help of a neoclassical trade model in which country size is at centre stage it is shown that a sufficient condition for a country to prefer a non cooperative nash tariff equilibrium retaliation over free trade is that its relative size be sufficiently large the paper also refines the structure of the general trade model and generates additional characterization results on the importance of country size for best response tariff functions retaliatory tariffs and welfare

combining farrell frontier and hedonic travel cost models for valuing estuarine quality a 1992 survey of tennessee anglers was used to determine who is fishing and how often the species they fish for and how anglers perceive the regulatory structure the results are based on telephone interviews with 450 active licensed an glers nearly 81 of the anglers visited a tennessee reservoir in 1992 while 41 fished warm water streams 28 farm ponds and 22 trout streams over 60 pre ferred separate regulations for reservoirs active reservoir fishermen were more likely to support individual regulations the participants were evenly split on whether a proposed regulation which has public support should be imposed even if the manage ment agency does not feel the fishery would benefit eighty percent of the anglers indicated that existing fishing regulations were not complicated proc annu conf southeast assoc fish and wildl agencies 47 767 774 proper administration of fishery resources requires management authorities to have knowledge of the angler population served by the management agency specifically authorities should be aware of the type and intensity of angler activi ties and understand angler preferences concerning existing and proposed management alternatives to the degree that certain types of fishermen are less likely to support management policies authorities should target educational pro grams specifically at non supportiv e anglers to gain greater public support for biologically viable management strategies this study uses data gathered from a survey of tennessee anglers to deter mine who is fishing and how often the species they are targeting and how anglers perceive the regulatory structure we report the demographic factors of anglers which exhibit statistically significant relationships to angler support for the current

a comparison of user benefits and costs of nature conservation at three nature reserves willis k g and benson j f 1988 a comparison of user benefits and costs of nature conservation at three nature reserves reg studies 22 417 228 benefits from conserving wildlife at three sites of special scientific interest are estimated using a travel cost method recording demand in terms of actual site visits these benefits are compared to the costs of nature conservation both the financial cost which is or could be incurred under the wildlife and countryside act 1981 and also the social costs of the agricultural output forgone after protective tariffs and subsidies of the common agricultural policy have been removed willis k g et benson j f 1988 une comparaison des avantages et des couts de la defense de l environnement aux usagers a trois reserves naturelles reg studies 22 417 228 on estime les avantages de la protection de la faune a trois sites d inter t scientifique special a partir d une methode qui calcule les frais de trajet enregistrant la demande en fonction des visi

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

estimating the structural equations of implicit markets and household production functions whenever marginal prices are nonconstant as in most hedonic and household production function markets ordinary least squares estimates of the price elasticities of structural equations will be biased a two stage least squares estimation procedure is developed and applied to estimate hedonic and potentially household production function demand functions when price gradients are nonlinear

optimal asset allocation for aggregated defined benefit pension funds with stochastic interest rates in this paper we study the optimal management of an aggregated pension fund of defined benefit type in the presence of a stochastic interest rate we suppose that the sponsor can invest in a savings account in a risky stock and in a bond with the aim of minimizing deviations of the unfunded actuarial liability from zero along a finite time horizon we solve the problem by means of optimal stochastic control techniques and analyze the influence on the optimal solution of some of the parameters involved in the model

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