Abstract

Forecasters regularly make point predictions of future events. Recipients of the predictions may use them to inform their own assessments and decisions. This paper integrates and extends my past analyses of several simple but inadequately appreciated logical issues that affect interpretation of point predictions. I explain the algebraic basis for a pervasive empirical finding that the cross-sectional mean or median of a set of point predictions is more accurate than the individual predictions used to form the mean or median, a phenomenon sometimes called the “wisdom of crowds.” I call attention to difficulties in interpretation of point predictions expressed by forecasters who are uncertain about the future. I consider the connection between predictions and reality. In toto, the analysis questions prevalent prediction practices that use a single combined prediction to summarize the beliefs of multiple forecasters.

Causal Inferences in Capital Markets Research

This article is included as a chapter in Causal Inferences in Capital Markets Research.

Causal Inferences in Capital Markets Research is an attempt to promote a broad interdisciplinary debate about the notion of causality and the role of causal inference in the social sciences.

At the risk of oversimplifying, the issue of causality divides the accounting research community in two polar views: the view that causality is an unattainable ideal for the social sciences and must be given up as a standard, and the view that, on one hand, causality should be the ultimate goal of all scientific endeavors and, on the other hand, theory and causal inference are inextricable. Reflecting and discussing these views was the main motivation for this volume. This volume contains eight articles on three topics: I) Econometrics; III) Accounting, and III) Finance.

First, Nancy Cartwright addresses the problem of external validity and the reliability of scientific claims that generalize individual cases. Then, John Rust discusses the role of assumptions in empirical research and the possibility of assumption-free inference. Peter Reiss considers the question how sensitive are instrumental variables to functional form transformations. Finally, Charles Manski studies the logical issues that affect the interpretation of point predictions.

Second, Jeremy Bertomeu, Anne Beyer and Daniel Taylor provide a critical overview of empirical accounting research focusing on the benefits of theory-based estimation, while Qi Chen and Katherine Schipper consider the question whether all research should be causal and assess the existing gap between theory and empirical research in accounting.

Third, R. Jay Kahn and Toni Whited clarifies and contrasts the notions of identification and causality, whereas Ivo Welch adopts a sociology of science approach to understand the consequences of the researchers’ race for discovering novel and surprising results.

This volume allows researchers and Ph.D students in accounting, and the social sciences in general, to acquire a deeper understanding of the notion of causality and the nature, limits, and scope of empirical research in the social sciences.