Experimental Methods and the Welfare Evaluation of Policy Lotteries

Policies impose lotteries of outcomes on individuals, since we never know exactly what the effects of the policy will be. In order to evaluate alternative policies, we therefore need to make some assumptions about individual preferences, even before social welfare functions are applied. Instead of making a priori assumptions about those preferences that are likely to be wrong, there are two broad ways in which experimental methods are used to evaluate policy. One is to use experiments to estimate individual preferences, valuations and beliefs, and use those estimates as priors in the evaluation of policy. The other approach is to undertake deliberate randomization, or exploit accidental or natural randomization, to infer the effects of policy. The strengths and weaknesses of these approaches are reviewed, and their complementarities identified.

The Methodologies of Neuroeconomics

We critically review the methodological practices of two research programs which are jointly called 'neuroeconomics'. We defend the first of these, termed 'neurocellular economics' (NE) by Ross (2008), from an attack on its relevance by Gul and Pesendorfer (2008) (GP). This attack arbitrarily singles out some but not all processing variables as unimportant to economics, is insensitive to the realities of empirical theory testing, and ignores the central importance to economics of 'ecological rationality' (Smith 2007). GP ironically share this last attitude with advocates of 'behavioral economics in the scanner' (BES), the other, and better known, branch of neuroeconomics. We consider grounds for skepticism about the accomplishments of this research program to date, based on its methodological individualism, its ad hoc econometrics, its tolerance for invalid reverse inference, and its inattention to the difficulties involved in extracting temporally lagged data if people's anticipation of reward causes pre-emptive blood flow.

Testing for Parameter Instability using the R/S Statistic

This paper explores the use of the R/S statistic as a means of checking for parameter instability. The nature and properties of the statistic are described, and its behaviour and power in the context of three situations of structural change are examined. The results suggest that the R/S statistic has an ability to detect shifts in means and changes in the intercept of a regression relationship. Moreover, it is more powerful than the OLS variant of the well known cumulative sum of squares residual test for detecting unknown structural breaks in the cases involving the linear regression models that were examined. It would therefore seem to us that the application of the R/S statistic to the problem of testing for structural instability is worthy of further investigation.

Multilateral negotiations over climate change policy

Negotiations in the real world have many features which tend to be ignored inpolicy modeling. They are often multilateral, involving many negotiating parties with preferences over outcomes that can differ substantially. They are also often multi-dimensional,in the sense that several policies are negotiated over simultaneously. Trade negotiations are a prime example, as are negotiations over environmental policies toabate carbon dioxide. We demonstrate how one can formally model this type of negotiation process. We use a policy-oriented computable general equilibrium model to generate preference functions which are then used in a formal multilateral bargaining game. The case study is to climate change policy, but the main contribution is to demonstrate how one can integrate formal economic models of the impacts of policies with formal bargaining models of the negotiations over those policies.CGE, bilateral bargaining, CO2, Climate Change

Naturally Occurring Markets and Exogenous Laboratory Experiments: A Case Study of the Winner's Curse

There has been a dramatic increase in the use of experimental methods in the past two decades. An oft-cited reason for this rise in popularity is that experimental methods provide the necessary control to estimate treatment effects in isolation of other confounding factors. We question the relevance of experimental findings from laboratory settings that abstract from the field context of the task that theory purports to explain. Using common value auction theory as our guide, we identify naturally occurring settings in which one can test the theory. In our treatments the subjects are not picked at random, as in lab experiments with student subjects, but are deliberately identified by their trading roles in the natural field setting. We find that experienced agents bidding in familiar roles do not fall prey to the winner's curse. Yet, when experienced agents are observed bidding in an unfamiliar role, we find that they frequently fall prey to the winner's curse. We conclude that the theory predicts field behavior well when one is able to identify naturally occurring field counterparts to the key theoretical conditions.

Naturally Occurring Markets and Exogenous Laboratory Experiments: A Case Study of the Winner's Curse

There has been a dramatic increase in the use of experimental methods in the past two decades. An oft-cited reason for this rise in popularity is that experimental methods provide the necessary control to estimate treatment effects in isolation of other confounding factors. We examine the relevance of experimental findings from laboratory settings that abstract from the field context of the task that theory purports to explain. Using common value auction theory as our guide, we identify naturally occurring settings in which one can test the theory. In our treatments the subjects are not picked at random, as in lab experiments with student subjects, but are deliberately identified by their trading roles in the natural field setting. We find that experienced agents bidding in familiar roles do not fall prey to the winner's curse. Yet, when experienced agents are observed bidding in an unfamiliar role, we find that they frequently fall prey to the winner's curse. We conclude that the theory predicts field behavior well when one is able to identify naturally occurring field counterparts to the key theoretical conditions.

Can Intertemporal Choice Experiments Elicit Time Preferences for Consumption? Yes

The most popular experimental method for eliciting time preferences involves subjects making choices over smaller, sooner amounts of money and larger, later amounts of money. Under some theoretically possible configurations of preferences and procedures, the discount rates inferred from these choices could lead to misleading inferences about time preferences for consumption. Using a direct empirical test, we show that those configurations of preferences are empirically implausible.

The Independence Axiom and the Bipolar Behaviorist

Developments in the theory of risk require yet another evaluation of the behavioral validity of the independence axiom. This axiom plays a central role in most formal statements of expected utility theory, as well as popular alternative models of decision-making under risk, such as rank-dependent utility theory. It also plays a central role in experiments used to characterize the way in which risk preferences deviate from expected utility theory. If someone claims that individuals behave as if they "probability weight" outcomes, and hence violate the independence axiom, it is invariably on the basis of experiments that must assume the independence axiom. We refer to this as the Bipolar Behavioral Hypothesis: behavioral economists are pessimistic about the axiom when it comes to characterizing how individuals directly evaluate two lotteries in a binary choice task, but are optimistic about the axiom when it comes to characterizing how individuals evaluate multiple lotteries that make up the incentive structure for a multiple-task experiment. Building on designs that have a long tradition in experimental economics, we offer direct tests of the axiom and the evidence for probability weighting. We reject the Bipolar Behavioral Hypothesis: we find that nonparametric preferences estimated for the rank-dependent utility model are significantly affected when one elicits choices with procedures that require the independence assumption, as compared to choices with procedures that do not require that assumption. We also demonstrate this result with familiar parametric preference specifications, and draw general implications for the empirical evaluation of theories about risk.