Peter Norman Sørensen

Information aggregation in debate: who should speak first?

Abstract Privately informed individuals speak openly in front of other members of a committee about the desirability of a public decision. Each individual wishes to appear well informed. For any given order of speech, committee members may herd by suppressing their true information. With individuals of heterogeneous expertise, optimizing over the order of speech can improve the extraction of information, but not perfectly so. It is not always optimal to use the common anti-seniority rule whereby experts speak in order of increasing expertise. A committee with more able experts may be afflicted by greater herding problems, yielding a worse outcome.

Rational Social Learning by Random Sampling

This paper explores rational social learning in which everyone only sees unordered random samples from the action history. In this model, herds need not occur when the distant past can be sampled. If private signal strengths are unbounded and the past is not over-sampled -- not forever affected by any individual -- there is complete learning and a correct proportionate herd. With recursive sampling, welfare almost surely converges under the new proviso that the recent past is not over-sampled. In this case, there is almost surely complete learning with unbounded beliefs and unit sample sizes. The sampling noise in this Polya urn model induces a path-dependent structure, so that re-running the model with identical signals generally produces different outcomes.

The Favorite-Longshot Bias: An Overview of the Main Explanations

In betting markets, the expected return on longshot bets tends to be systematically lower than on favorite bets. This favorite-longshot bias is a widely documented empirical fact, often perceived to be an important deviation from the market efficiency hypothesis. This chapter presents an overview of the main theoretical explanations for this bias proposed in the literature.

Aggregation of Information and Beliefs: Asset Pricing Lessons from Prediction Markets

In a binary prediction market in which risk-neutral traders have heterogeneous prior beliefs and are allowed to invest a limited amount of money, the static rational expectations equilibrium price is demonstrated to underreact to information. This effect is consistent with a favorite-longshot bias, and is more pronounced when prior beliefs are more heterogeneous. Relaxing the assumptions of risk neutrality and bounded budget, underreaction to information also holds in a more general asset market with heterogeneous priors, provided traders have decreasing absolute risk aversion. In a dynamic asset market, the underreaction of the first period price is followed by momentum.

Chapter 12 – Forecasters’ Objectives and Strategies

Abstract This chapter develops a unified modeling framework for analyzing the strategic behavior of forecasters. The theoretical model encompasses reputational objectives, competition for the best accuracy, and bias. Also drawing from the extensive literature on analysts, we review the empirical evidence on strategic forecasting and illustrate how our model can be structurally estimated.

INTRODUCTION TO SPECIAL ISSUE: DYNAMIC MACROECONOMIC THEORY

This issue collects 11 articles at the frontier of the field of Dynamic Macroeconomic Theory.A majority of the articles discuss theoretical issues related to monetary policy. Many rich economies have now enjoyed a long period of stable monetary conditions, but many researchers remain puzzled as to what are the main mechanisms driving monetary stability. The field is of great importance to policymakers, and this issues dynamic approaches will advance the debate. The other articles touch on other, equally inherently dynamic issues of macroeconomics, relating to growth, business cycles, and the role of credit. In light of the hard constraints we imposed on the length of the contributed articles, we will let the articles speak for themselves, and hope that the reader will enjoy this research sample as much as we do.

Giffen Demand for Several Goods

The utility maximizing consumer’s demand function may simultaneously possess the Giffen property for any number of goods strictly less than all. By way of a simple example it is possible to illuminate the preference characteristics conducive to such a result.

Are the Intraday Effects of Central Bank Intervention on Exchange Rate Spreads Asymmetric and State Dependent

This paper investigates the intraday effects of unannounced foreign exchange intervention on bid-ask exchange rate spreads using official intraday intervention data provided by the Danish central bank. Our starting point is a simple theoretical model of the bid-ask spread which we use to formulate testable hypotheses regarding how unannounced intervention purchases and intervention sales influence the market asymmetrically. To test these hypotheses we estimate weighted least squares (WLS) time-series models of the intraday bid-ask spread. Our main result is that intervention purchases and sales both exert a significant influence on the exchange rate spread, but in opposite directions: intervention purchases of the smaller currency, on average, reduce the spread while intervention sales, on average, increase the spread. We also show that intervention only affects the exchange rate spread when the state of the market is not abnormally volatile. Our results are consistent with the notion that illiquidity arises when traders fear speculative pressure against the smaller currency and confirms the asymmetry hypothesis of our theoretical model.