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Journal of Finance Vol. 64 No. 4 2009

Predictive Systems: Living with Imperfect Predictors

Ľuboš Pástor; Robert F. Stambaugh1,2,3,4,5

1 Conference Board · 2 Faculdades Guarulhos · 3 Campbell Collaboration · 4 Ospedale San Pietro Fatebenefratelli · 5 University of Hong Kong

Abstract

We develop a framework for estimating expected returns—a predictive system —that allows predictors to be imperfectly correlated with the conditional expected return. When predictors are imperfect, the estimated expected return depends on past returns in a manner that hinges on the correlation between unexpected returns and innovations in expected returns. We find empirically that prior beliefs about this correlation, which is most likely negative, substantially affect estimates of expected returns as well as various inferences about predictability, including assessments of a predictor's usefulness. Compared to standard predictive regressions, predictive systems deliver different expected returns with higher estimated precision.

DOI
10.1111/j.1540-6261.2009.01474.x
Volume
64
Issue
4
Pages
1583-1628
Language
en
Sources
crossref openalex

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