Glenn W Harrison, Morten I Lau, Elisabet E Rutstrom
Cited by*: 14 Downloads*: 22

Evidence that individuals have dynamically consistent preferences is usually generated by studying the discount rates of the individual over different horizons, but where those rates are elicited at a single point in time. If these elicited discount rates vary by horizon, the individual is typically claimed to have preferences that imply a dynamic inconsistency, although this inference requires additional assumptions such as intertemporal separability. However, what one really wants to know is if the same subject has the same discount rate function when that individual is asked at a later point in time. Such panel tests then require that one allow for possible changes in the states of nature that the subject faces, since they may confound any in-sample comparisons of discount rate functions at different points in time. We report the results of a large-scale panel experiment undertaken in the field that allows us to examine this issue. In June 2003, we elicited subjective discount rates from 253 subjects, representative of the adult Danish population. Between September 2003 and November 2004, we re-visited 97 of these subjects and repeated these tasks. In each visit, we also elicited information on their individual characteristics, as well as their expectations about the state of their own economic situation and macroeconomic variables. We find evidence in favor of dynamic consistency.
Glenn W Harrison, Morten I Lau, Elisabet E Rutstrom, Melonie B Williams
Cited by*: 29 Downloads*: 303

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.
Glenn W Harrison, Morten I Lau, Elisabet E Rutstrom, Melonie B Williams
Cited by*: 219 Downloads*: 30

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.
Glenn W Harrison, Morten I Lau, Elisabet E Rutstrom
Cited by*: 378 Downloads*: 31

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. Copyright The editors of the "Scandinavian Journal of Economics" 2007 .
Steffen Andersen, Glenn W Harrison, Morten I Lau, Elisabet E Rutstrom
Cited by*: 4 Downloads*: 16

Economists recognize that preferences can differ across individuals. We examine the strengths and weaknesses of lab and field experiments to detect differences in preferences that are associated with standard, observable characteristics of the individual. We consider preferences over risk and time, two fundamental concepts of economics. Our results provide striking evidence that there are good reasons to conduct field experiments. The lab fails to detect preference heterogeneity that is present in the field, obviously due to the demographic homogeneity of the lab. There are also differences in treatment effects measured in the lab and the field that can be traced to interactions between treatment and demographic effects. These can only be detected and controlled for properly in the field data. Thus one cannot simply claim, without additional empirical argument or assumption, that treatment effects estimated in the lab are reliable.
Glenn W Harrison, Morten I Lau, Elisabet E Rutstrom
Cited by*: 0 Downloads*: 10

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.
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