Time preferences and risk aversion: Tests on domain differences

Understanding how individuals discount and evaluate the risks of environmental outcomes is a prime component in designing effective environmental policy. We use an incentivized experimental design to investigate whether subjects’ time preferences and risk aversion across the monetary and environmental domains differ. We find that subjects’ time preferences are not significantly different across the two domains. In contrast, subjects exhibit a higher degree of risk aversion in the environmental domain. Furthermore, we corroborate earlier results, documenting that women are more risk averse than men in the monetary domain, and show this finding to also hold in the environmental domain.     

Experimental evidence on the irreversebility effect

This paper presents the results of an experimental investigation on how increased expected information affects subjects' choices. We show that Claude Henry's (1974) result (the Irreversibility Effect) is strongly supported by our experimental data. According to the Irreversibility Effect a rational (expected utility maximizing) agent who anticipates more information before making his future choices, will take a less irreversible position today. In our experiment, present and future choices are framed respectively as portfolio and investment decisions. The degree of irreversibility (or flexibility) chosen by experimental subjects in response to additional information indicated that subjects react to anticipated information as predicted by theory.     

Regret aversion or event-splitting effects? more evidence under risk and uncertainty

Recent experimental evidence has concluded that experimentally observed juxtaposition effects, as predicted by regret theory¹, are largely attributable to “event-splitting effects” (ESEs) whereby the subjective decision weight attached to an outcome depends on the number of, as well as on the combined probability of, the disjoint events in which that outcome occurs. An experiment is reported that discriminates between juxtaposition effects and ESEs under conditions of both complete and incomplete information. The results confirm that juxtaposition effects are indeed largely due to ESEs and are robust over different informational conditions.     

The impact of risk aversion and ambiguity aversion on annuity and saving choices

Journal of Risk and Uncertainty - We analyze the impact of risk aversion and ambiguity aversion on the competing demands for annuities and bequeathable savings using a lifecycle recursive utility...     

On the definition of risk aversion

Two definitions of risk aversion have recently been proposed for non-expected utility theories of choice under uncertainty: the former refers the measure of risk aversion (Montesano 1985, 1986 and 1988) directly to the risk premium (i.e. to the difference between the expected value of the action under consideration and its certainty equivalent); the latter defines risk aversion as a decreasing preference for an increasing risk (introduced as mean preserving spreads) (Chew, Karni and Safra 1987, Machina 1987, Röell 1987, Yaari 1987).When the von Neumann-Morgenstern utility function exists both these definitions indicate an agent as a risk averter if his or her utility function is concave. Consequently, the two definitions are equivalent. However, they are no longer equivalent when the von Neumann-Morgenstern utility function does not exist and a non-expected utility theory is assumed. Examples can be given which show how the risk aversion of the one definition can coexist with the risk attraction of the other. Indeed the two definitions consider two different questions: the risk premium definition specifically concerns risk aversion, while the mean preserving spreads definition concerns the increasing (with risk) risk aversion.The mean preserving spreads definition of risk aversion, i.e. the increasing (with risk) risk aversion, requires a special kind of concavity for the preference function (that the derivatives with respect to probabilities are concave in the respective consequences). The risk premium definition of local risk aversion requires that the probability distribution dominates on the average the distribution of the derivatives of the preference function with respect to consequences. Besides, when the local measure of the first order is zero, there is risk aversion according to the measure of the second order if the preference function is concave with respect to consequences.Yaari's (1969) measure of risk aversion is closely linked to the r.p. measure of the second order. Its sign does not indicate risk aversion (if positive) or attraction (if negative) when the measure of the first order is not zero (i.e., in Yaari's language, when subjective odds differ from the market odds).     

Risk aversion,downside risk aversion,and the transition to entrepreneurship

In this paper, we discuss the transition from secure employment to risky self-employment (entrepreneurship) caused by a small increase in wealth. Building on the apportioning risk literature, we prove that the transition from secure employment to risky entrepreneurship is based on a measure of the difference between the strength of downside risk aversion and the strength of risk aversion. This result highlights the idea that using the behavioral approach of risky lotteries to study entrepreneurship can produce different results from the traditional economic theory of entrepreneurship, which can have policy implications that must be considered with caution.

     

School environment and risk preferences: Experimental evidence

Using a field experiment with high school students, we evaluate the development of risk preferences. Examining the impact of school characteristics on preference development reveals both peer and quality effects. For the peer effect, individuals in schools with a higher percentage of students on free or reduced lunches (hence a higher proportion of low-income peers with whom to interact) are significantly more risk averse. For the quality effect, individuals in schools with smaller class sizes and a higher percentage of educators with advanced degrees have higher, more moderate levels of risk aversion. We further discuss economic, cognitive and emotional development theories of risk preferences. Data show demographic-related patterns: girls are more risk averse on average, while taller and nonwhite individuals are more risk tolerant.     

On the intensity of downside risk aversion

The degree of downside risk aversion (or equivalently prudence) is so far usually measured by . We propose here another measure, , which has specific and interesting local and global properties. Some of these properties are to a wide extent similar to those of the classical measure of absolute risk aversion, which is not always the case for . It also appears that the two measures are not mutually exclusive. Instead, they seem to be rather complementary as shown through an economic application dealing with a simple general equilibrium model of savings.

Monetary incentives in the loss domain and behavior toward risk: An experimental comparison of three reward schemes including real losses

In the loss domain, both practical and ethical considerations rule out the systematic use of an incentive-compatible procedure involving real losses. The experimental study presented here aims at investigating whether some easier-to-implement procedure could be adequately used. For that purpose, the subjects’ degree of risk aversion is compared across three payment conditions: a real-losses condition based on a random-lottery (incentive-compatible) system, which serves as a benchmark, and two challengers, namely a “losses-from-an-initial-endowment” procedure and a hypothetical-losses condition. As a by-product, our experimental design also allows us to investigate the impact of monetary incentives in the gain domain. The main result is twofold: no significant difference arises between the three payment conditions in the loss domain, while real and hypothetical choices significantly differ in the gain domain. Our results suggest that the use of monetary incentives may be more crucial in the gain domain than in the loss domain.     

Ross' measure of risk aversion and portfolio selection

This article shows that if Ross' definition of riskier is replaced by a more traditional definition, such as a mean-preserving spread or second-degree stochastic dominance, then the application of Ross's stronger measure of risk aversion to the portfolio problem may no longer produce the desired result. It is also shown that the stronger measure may not perform satisfactorily when applied to exponential utility functions.The authors are grateful to John Pratt for his helpful comments.     

Measures of risk aversion with expected and nonexpected utility

In the expected utility case, the risk-aversion measure is given by the Arrow-Pratt index. Three proposals of a risk-aversion measure for the nonexpected utility case are examined. The first one sets “the second derivative of the acceptance frontier as a measure of local risk aversion.” The second one takes into account the concavity in the consequences of the partial derivatives of the preference function with respect to probabilities. The third one measures risk aversion through the ratio between the risk premium and the standard deviation of the lottery. The third proposal catches the main feature of risk aversion, while the other two proposals are not always in accordance with the same crude definition of risk aversion, by which there is risk aversion when an agent prefers to get the expected value of a lottery rather than to participate in it.     

Risk and risk aversion effects in contests with contingent payments

Contests by their very nature involve risk, winning and losing are both possible, and the gain from winning can itself be uncertain. The participants in a contest use resources to increase their chance of winning. The main focus of this analysis is on the effects of risk aversion and risk in contests where only winners pay for resources used to compete. When payment is contingent on winning, the effect of risk aversion is in the opposite direction of what occurs when costs are paid by both winners and losers. A number of contests observed in the marketplace that exhibit this contingent payment property are discussed.     

Mixed risk aversion and preference for risk disaggregation: a story of moments

In a recent article entitled “Putting Risk in its Proper Place,” Eeckhoudt and Schlesinger (2006) established a theorem linking the sign of the n-th derivative of an agent’s utility function to her preferences among pairs of simple lotteries. We characterize these lotteries and show that, in a given pair, they only differ by their moments of order greater than or equal to n. When the n-th derivative of the utility function is positive (negative) and n is odd (even), the agent prefers a lottery with higher (lower) n + 2p-th moments for p belonging to the set of positive integers. This result links the preference for disaggregation of risks across states of nature to the complete structure of moments preferred by mixed risk averse agents. It can be viewed as a generalization of a proposition appearing in Ekern (1980) which focused only on the differences in the n-th moments.     

Positivity of bid-ask spreads and symmetrical monotone risk aversion*

A usual argument in finance refers to no arbitrage opportunities for the positivity of the bid-ask spread. Here we follow the decision theory approach and show that if positivity of the bid-ask spread is identified with strong risk aversion for an expected utility market-maker, this is no longer true for a rank-dependent expected utility one. For such a decision-maker only a very weak form of risk aversion is required, a result which seems more in accordance with his actual behavior. We conclude by showing that the no-trade interval result of Dow and Werlang (1992a) remains valid for a rank-dependent expected utility market-maker merely exhibiting this weak form of risk aversion.     

Joint measurement of risk aversion,prudence, and temperance

Risk aversion—but also the higher-order risk preferences of prudence and temperance—are fundamental concepts in the study of economic decision making. We propose a method to jointly measure the intensity of risk aversion, prudence, and temperance. Our theoretical approach is to define risk compensations of different orders, and in an experiment we elicit these compensations with a price list technique. We find evidence for risk aversion, prudence, and temperance. These traits correlate within subjects. The compensations elicited for prudence are significantly larger than those for risk aversion and temperance. In contrast to commonly used utility functions, prospect theory can predict this behavioral pattern. In our experiment, risk-averse, risk-loving, and risk-neutral subjects are prudent. This supports a recent theoretical observation that prudence may be a more universal trait than previously realized.     

Rationality on the rise: Why relative risk aversion increases with stake size

How does risk tolerance vary with stake size? This important question cannot be adequately answered if framing effects, nonlinear probability weighting, and heterogeneity of preference types are neglected. We show that the observed increase in relative risk aversion over gains cannot be captured by the curvature of the value function. Rather, it is predominantly driven by a change in probability weighting of a majority group of individuals who weight probabilities of high gains more conservatively. Contrary to gains, no coherent change in relative risk aversion is observed for losses. These results not only challenge expected utility theory, but also prospect theory.     

An experimental investigation of the ‘tenuous trade-off’ between risk and incentives in organizations

Theory and Decision - We investigate experimentally the relationship between risk and incentives in a principal–agent setting. In contrast to the existing empirical literature that describes...     

Catastrophe avoidance and risk aversion: Implications of formal utility maximization

It is shown that von Neumann-Morgernstern (NM) expected utility maximization, as is currently practised, implies an upper bound on the percentage utility that can be sacrificed to reduce the probability or severity of a catastrophe. The major quantitative result of this paper is a simple tabular (and graphic) presentation of the maximum allowed budget for catastrophe prevention/abatement within the NM framework. The upper limit, which declines in proportion to catastrophe probability, effectively reduces the benefit-cost ratio for catastrophe protection. Use of formal utility maximization methods can thus result in the choice of policies that fail to avoid catastrophes that could be avoided at relatively low cost. Thus the decisions of risk-averse, risk-neutral, and risk-seeing utility maximizers tend to converge in catastrophe prone situations. The prospect theory of Kahneman and Tversky or the elasticity principle of Bernard offer more flexible options of risk aversion under these circumstances.Professor of Engineering and Public Policy, Carnegie-Mellon University, Pittsburgh.PhD candidate in Engineering and Public Policy, Carnegie-Mellon University, Pittsburgh and Assistant Professor, College of Business Administration, University of Nevada, Reno.     

Process fairness,outcome fairness,and dynamic consistency: Experimental evidence for risk and ambiguity

Literature on fairness preferences distinguishes between outcome fairness, concerning the final allocation of payoffs, and process fairness, concerning the expected allocation of payoffs. It is not obvious, however, whether process fairness can consistently be implemented. Once uncertainty is resolved and outcomes are determined, the ex-ante procedurally fair decision maker may become consequentialist ex-post, and reconsider her choice on the basis of the observed outcomes. We present experimental evidence on dynamic consistency of social preferences under both known risk and ambiguity. A significant share of people subscribe to process fairness both before and after the resolution of uncertainty.