Measuring revisions to subjective expectations

This paper develops a new metric to measure revisions to subjective expectations and proposes a survey design strategy that enables the estimation of the metric. As an application, I analyze how women update their ex pectations about the effectiveness of contraception methods. The women interviewed exhibit substantial heterogeneity in the way they revise their expectations with receipt of the same information. When relating the heterogeneity in the updating process to observable characteristics, I find that schooling, having a regular sexual partner and knowledge and use of birth control methods have a large impact on the revision process about the effectiveness of contraceptives.

Valuing publicly sponsored research projects: Risks,scenario adjustments,and inattention

Survey-based choice scenarios used to value non-market public goods typically preclude any risk that the benefits described may not be delivered. Our survey specifies explicit risks of (a) outright program failure and (b) program redundancy due to possible private sector substitutes. Additionally, most analyses assume that survey subjects fully accept these scenarios and that all provided information receives their complete attention. Our discounted expected utility model of choice accommodates both these objective risks and the possibility of subjective scenario adjustment or selective inattention by respondents. We then counterfactually simulate willingness-to-pay in the absence of these distortions.

Self-protection and insurance with interdependencies

We study optimal investment in self-protection of insured individuals when they face interdependencies in the form of potential contamination from others. If individuals cannot coordinate their actions, then the positive externality of investing in self-protection implies that, in equilibrium, individuals underinvest in self-protection. Limiting insurance coverage through deductibles or selling “at-fault” insurance can partially internalize this externality and thereby improve individual and social welfare.

Whom should we believe? Aggregation of heterogeneous beliefs

We examine the collective risk attitude of a group with heterogeneous beliefs. We prove that the wealth-dependent probability distribution used by the representative agent is biased in favor of the beliefs of the more risk tolerant consumers. Moreover, increasing disagreement on the state probability raises the state probability of the representative agent. It implies that when most disagreements are concentrated in the tails of the distribution, the perceived collective risk is magnified. This can help to solve the equity premium puzzle. We show that the trade volume and the equity premium are positively correlated.

One-reason decision-making: Modeling violations of expected utility theory

People violate expected utility theory and this has been traditionally modeled by augmenting its weight-and-add framework by nonlinear transformations of values and probabilities. Yet individuals often use one-reason decision-making when making court decisions or choosing cellular phones, and institutions do the same when creating rules for traffic safety or fair play in sports. We analyze a model of one-reason decision-making, the priority heuristic, and show that it simultaneously implies common consequence effects, common ratio effects, reflection effects, and the fourfold pattern of risk attitude. The preferences represented by the priority heuristic satisfy some standard axioms. This work may provide the basis for a new look at bounded rationality.

Valuing risks of death from terrorism and natural disasters

This paper uses a random utility model to examine stated preferences for the valuation of public risks of fatalities from terrorist attacks and natural disasters. Traffic-related deaths serve as the common reference point in two series of pairwise risk-risk tradeoff choices. Even after taking into account differences in respondent risk beliefs, the nationally representative sample values the prevention of terrorism deaths almost twice as highly as preventing natural disaster deaths and at about the same level as preventing deaths from traffic accidents, which pose greater personal risk. Education, seatbelt usage, political preferences, and terrorism risk beliefs affect valuations in the expected manner.

Eliciting decision weights by adapting de Finetti’s betting-odds method to prospect theory

This paper extends de Finetti’s betting-odds method for assessing subjective beliefs to ambiguous events. Thus, a tractable manner for measuring decision weights under ambiguity is obtained. De Finetti’s method is so transparent that decision makers can evaluate the relevant tradeoffs in complex situations. The resulting data can easily be analyzed, using nonparametric techniques. Our extension is implemented in an experiment on predicting next-day’s performance of the Dow Jones and Nikkei stock indexes, where we test the existence and nature of rank dependence, finding usual patterns. We also find violations of rank dependence.

Smoking,information sources,and risk perceptions—New results on Swedish data

Using data on Swedish adolescents, this study examines (1) perceptions of the addictiveness and mortality risk of smoking, (2) the effects of these perceptions on smoking behaviour, and (3) the role of various smoking risk information sources. The average respondent believed that 46 out of 100 smokers would die from diseases caused by their smoking. As to addictiveness perceptions, the average respondent believed that 68 out of 100 smokers trying to quit would not succeed. Both a higher perceived addictiveness and a higher perceived mortality risk were negatively related to smoking participation. The results showed substantial variation in the weight that the teenagers attached to the various information sources.

The sensitivity of subjective probability to time and elicitation method

The paper reports the results of a survey designed to elicit probability judgements for different types of events: ‘pure chance’ events, for which objective probabilities can be calculated; ‘public’ events, about which there may be some discussion in social groups and the media; and ‘personal’ events, such as those relating to crime or accidental injury. Even among respondents deemed to be ‘well-calibrated’ in the domain of pure chance events we find limited sensitivity to the ‘temporal scope’ of public and personal events—this being especially marked for personal events. We discuss possible reasons and some implications for policy-related survey work.

Conditional payments and self-protection

Self-protection can be financed either by upfront payments or by conditional payments (or contingent fees) in which individuals pay a provider only when a favorable outcome is realized. We find that, from the vantage point of a risk-averse individual, conditional payments welfare dominate upfront payments in the state-independent framework, but upfront payments welfare dominate conditional payments in the state-dependent framework. Moreover, more risk aversion always implies more self-protection under conditional payments, for both state-independent and state-dependent frameworks. In contrast, it has been previously argued that more risk aversion does not necessarily imply more self-protection under upfront payments.

Individual and group decision making under risk: An experimental study of Bayesian updating and violations of first-order stochastic dominance

This paper reports the results of experiments designed to test whether individuals and groups abide by monotonicity with respect to first-order stochastic dominance and Bayesian updating when making decisions under risk. The results indicate a significant number of violations of both principles. The violation rate when groups make decisions is substantially lower, and decreasing with group size, suggesting that social interaction improves the decision-making process. Greater transparency of the decision task reduces the violation rate, suggesting that these violations are due to judgment errors rather than the preference structure. In one treatment, however, less complex decisions result in a higher error rates.

Does television terrify tourists? Effects of US television news on demand for tourism in Israel

We analyze the impact on US tourist flows to Israel of variations in both the actual intensity of the Israeli-Palestinian conflict and the intensity implicit in US television news coverage. Conditional on actual events, changes in reported conflict intensity could influence tourists because alternative sources of information are costly; this explanation is consistent with a rational choice model. However, television news could influence tourist behavior because of its emotional impact, or because it causes the conflict to be brought to mind more readily, increasing the subjective probability of conflict events. We find that tourists respond to variations in actual Israeli casualties and reported Palestinian casualties; both effects are large. Reports of Israeli casualties and unreported Palestinian casualties have no significant impact on tourist flows. These asymmetries are consistent with asymmetric information costs within a rational choice framework, but are more difficult to square with the alternative explanations for media influence.

Paying for permanence: Public preferences for contaminated site cleanup

We use conjoint choice questions to investigate the preferences of people in four cities in Italy for income and future/permanent mortality risk reductions delivered by contaminated site remediation policies. The VSL is €5.6 million for an immediate risk reduction. If the risk reduction takes place 20 years from now, the implied VSL is €1.26 million. Respondents’ implicit discount rate is 7%. The VSL depends on respondent characteristics, familiarity with contaminated sites, concern about the health effects of exposure to toxicants, having a family member with cancer, perceived usefulness of public programs and beliefs about the goals of government remediation programs.

The effect of the background risk in a simple chance improving decision model

We experimentally investigate the effect of an independent and exogenous background risk to initial wealth on subjects’ risk attitudes and explore an appropriate incentive mechanism when identical or similar tasks are repeated in an experiment. Taking a simple chance improving decision model under risk where the winning probabilities are negatively related to the potential gain, we find that such a background risk tends to make risk-averse subjects behave more risk aversely. Furthermore, we find that risk-averse subjects tend to show decreasing absolute risk aversion (DARA), and that a random round payoff mechanism (RRPM) would control the possible wealth effect. This suggests that RRPM would be a better incentive mechanism for an experiment where repetition of a task is used.

Pre-commitment and flexibility in a time decision experiment

An agent with dynamically inconsistent preferences may deviate from her plan of action as the future draws near. An exponential discounter may do exactly the same when facing an uncertain future. Through an experiment we compare preference-based vs. uncertainty-based explanations for choice reversal over time by eliciting choices for pre-commitment and flexibility. Evidence of widespread commitment favors a preference-based explanation.

Adverse selection,moral hazard and propitious selection

We propose a simple model with preference-based adverse selection and moral hazard that formalizes the cherry picking/propitious selection argument. This argument assumes that individuals differ in risk aversion, potentially resulting in more risk averse agents buying more insurance while being less risky. The propitious selection argument is summarized by two properties: regularity (more risk averse agents exert more caution) and single-crossing (more risk averse agents have a higher willingness to pay for insurance). We show that these assumptions are incompatible with a pooling equilibrium, and that they do not imply a negative correlation between risk and insurance coverage at equilibrium.

Statistical vs. identified lives in benefit-cost analysis

Evaluation of projects that affect mortality risk usually assumes that risk changes are small and similar across individuals. In reality, risks differ among individuals and information about risk heterogeneity determines the extent to which affected lives are “statistical” or “identified” and influences the outcome of benefit-cost analysis (BCA). The effects of information about risk heterogeneity on BCA depend on, inter alia, whether information concerns heterogeneity of baseline or change in risk and whether valuation uses compensating or equivalent variation. BCA does not systematically favor identified over statistical lives. We suggest some political factors that may explain the apparent public bias.

Learning from mistakes: What do inconsistent choices over risk tell us?

We implement a risk experiment that allows for judgment errors to investigate who makes mistakes and whether it matters. The experiments are conducted with a random sample of the adult population in Rwanda, and data on financial decisions are collected. We find a high proportion of inconsistent choices, with over 50% of the participants making at least one mistake. Importantly, errors are informative. While risk aversion alone does not explain financial decisions, risk aversion and inconsistent choices interact in significant and sensible ways. As we would expect, risk-averse individuals are more likely to belong to a savings group and less likely to take out an informal loan. For those more likely to make mistakes, however, as they become more risk averse, they are less likely to belong to a savings group and more likely to take up informal credit, suggesting that mistakes correlate with less than optimal behavior.

Risk aversion and expected-utility theory: A calibration exercise

Rabin (Econometrica 68(5):1281–1292, 2000) argues that, under expected-utility, observed risk aversion over modest stakes implies extremely high risk aversion over large stakes. Cox and Sadiraj (Games Econom. Behav. 56(1):45–60, 2006) have replied that this is a problem of expected-utility of wealth, but that expected-utility of income does not share that problem. We combine experimental data on moderate-scale risky choices with survey data on income to estimate coefficients of relative risk aversion using expected-utility of consumption. Assuming individuals cannot save implies an average coefficient of relative risk aversion of 1.92. Assuming they can decide between consuming today and saving for the future, a realistic assumption, implies quadruple-digit coefficients. This gives empirical evidence for narrow bracketing.