Morten I. Lau

Estimating Individual Discount Rates in Denmark: A Field Experiment

We estimate individual discount rates with respect to time streams of money using controlled laboratory experiments. These discount rates are elicited by means of field experiments involving real monetary rewards. The experiments were carried out across Denmark using a representative sample of 268 people between 19 and 75 years of age. Individual discount rates are estimated for various households differentiated by socio-demographic characteristics such as income and age. Our conclusions are that discount rates are constant over the 12-month to 3-year horizons used in these experiments, and that discount rates vary substantially with respect to several socio-demographic variables. Hence we conclude that it would be reasonable to assume constant discount rates for specific household types, but not the same rates across all households.

Estimating Risk Attitudes in Denmark: A Field Experiment

We estimate individual risk attitudes using controlled experiments in the field in Denmark. The experiments were carried out across Denmark using a representative sample of 253 people between 19 and 75 years of age. Risk attitudes are estimated for various individuals differentiated by socio-demographic characteristics. Our results indicate that the average Dane is risk averse, and that risk neutrality is an inappropriate assumption to apply. We also find that risk attitudes vary significantly with respect to several important socio-demographic variables such as age and education. However, we do not find any effect of sex on risk attitudes.

Lost in State Space: Are Preferences Stable?

We use field experiments to examine the temporal stability of risk preferences. Over a 17-month period, we elicited risk preferences from subjects chosen to be representative of the adult Danish population. During this period we revisited many of these subjects and repeated a risk aversion elicitation task. We find some variation in risk attitudes over time, but we do not detect a general tendency for risk attitudes to increase or decrease over a 17-month span. The results also suggest that risk preferences are state contingent with respect to personal finances.

Eliciting risk and time preferences using field experiments: Some methodological issues

We design experiments to jointly elicit risk and time preferences for the adult Danish population. The experimental procedures build on laboratory experiments that have been evaluated using traditional subject pools. The field experiments utilize field sampling designs that we developed, and procedures that were chosen to be relatively transparent in the field with non-standard subject pools. Our overall design was also intended to be a general template for such field experiments in other countries. We examine the characterization of risk over a wider domain for each subject than previous experiments, allowing more precise estimates of risk attitudes. We also examine individual discount rates over six time horizons, as the first stage in a panel experiment in which we revisit subjects to test consistency and stability of responses over time. Risk and time preferences are heterogeneous, varying by observable individual characteristics. On a methodological level, we implement a refinement of existing procedures which elicits much more precise estimates, and also mitigates framing effects.

Risk Attitudes, Randomization to Treatment, and Self-Selection into Experiments

Randomization to treatment is fundamental to statistical control in the design of experiments. But randomization implies some uncertainty about treatment condition, and individuals differ in their preferences towards taking on risk. Since human subjects often volunteer for experiments, or are allowed to drop out of the experiment at any time if they want to, it is possible that the sample observed in an experiment might be biased because of the risk of randomization. On the other hand, the widespread use of a guaranteed show-up fee that is non-stochastic may generate sample selection biases of the opposite direction, encouraging more risk averse samples into experiments. We undertake a field experiment to directly test these hypotheses that risk attitudes play a role in sample selection. We follow standard procedures in the social sciences to recruit subjects to an experiment in which we measure their attitudes to risk. We exploit the fact that we know certain characteristics of the population sampled, adults in Denmark, allowing a statistical correction for sample selection bias using standard methods. We also utilize the fact that we have a complex sampling design to provide better estimates of the target population. Our results suggest that randomization bias is not a major empirical problem for field experiments of the kind we conducted if the objective is to identify marginal effects of sample characteristics. However, there is evidence that the use of show-up fees may have generated a sample that was more risk averse than would otherwise have been observed.

Approximating infinite-horizon models in a complementarity format : A primer in dynamic general equilibrium analysis

Abstract We demonstrate the advantages of the complementarity formulation for approximating infinite-horizon equilibria in neoclassical growth models as compared with techniques originally developed for optimal planning models. The complementarity approach does not require an ex ante specification of the growth rate in the terminal period and is therefore suitable for models with endogenous growth or short time horizons. We also consider approximation issues in models with multiple infinitely lived agents. Changes in net indebtedness over a finite period are estimated as part of the model to obtain a precise approximation of the infinite-horizon equilibria with a small number of time periods.

Individual discount rates and smoking: evidence from a field experiment in Denmark.

We elicit measures of individual discount rates from a representative sample of the Danish population and test two substantive hypotheses. The first hypothesis is that smokers have higher individual discount rates than non-smokers. The second hypothesis is that smokers are more likely to have time inconsistent preferences than non-smokers, where time inconsistency is indicated by a hyperbolic discounting function. We control for the concavity of the utility function in our estimates of individual discount rates and find that male smokers have significantly higher discount rates than male non-smokers. However, smoking has no significant association with discount rates among women. This result is robust across exponential and hyperbolic discounting functions. We consider the sensitivity of our conclusions to a statistical specification that allows each observation to potentially be generated by more than one latent data-generating process.

Valuation using multiple price list formats

We examine the properties of a popular method for elicitation of valuations from experimental subjects, the multiple price list format. The main advantages of this format are that it is relatively transparent to subjects and provides simple incentives for truthful revelation. The main disadvantages are that it only elicits interval responses, and could be susceptible to framing effects. We consider extensions to address and evaluate these concerns in the context of eliciting willingness to pay for products. We find that the multiple price list can elicit relatively precise valuations for products, and that those valuations are robust to possible framing effects. It therefore offers an attractive procedure for eliciting valuations for goods. ☆All data, instructions and statistical results are stored in the ExLab Digital Library at http://exlab.bus.ucf.edu

Dynamic Consistency in Denmark: A Longitudinal Field Experiment

We review experimental evidence collected from risky choice experiments using poor subjects in Ethiopia, India and Uganda. Using these data we estimate that just over 50% of our sample behaves in accordance with expected utility theory and that the rest subjectively weight probability according to prospect theory. Our results show that inferences about risk aversion are robust to whichever model we adopt when we estimate each model separately. However, when we allow both models to explain portions of the data simultaneously, we infer risk aversion for subjects behaving according to expected utility theory and risk seeking behavior for subjects behaving according to prospect theory. We conclude that the current practice of designing policies under the assumption that one or other explains all behavior is fundamentally flawed.We review experimental evidence collected from risky choice experiments using poor subjects in Ethiopia, India and Uganda. Using these data we estimate that just over 50% of our sample behaves in accordance with expected utility theory and that the rest subjectively weight probability according to prospect theory. Our results show that inferences about risk aversion are robust to whichever model we adopt when we estimate each model separately. However, when we allow both models to explain portions of the data simultaneously, we infer risk aversion for subjects behaving according to expected utility theory and risk seeking behavior for subjects behaving according to prospect theory. We conclude that the current practice of designing policies under the assumption that one or other explains all behavior is fundamentally flawed.

Risk aversion in game shows

We review the use of behavior from television game shows to infer risk attitudes. These shows provide evidence when contestants are making decisions over very large stakes, and in a replicated, structured way. Inferences are generally confounded by the subjective assessment of skill in some games, and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention.