The fundamental problem of external validity is not to generalize from one experiment, so much as to experimentally test generalizable theories. That is, theories that explain the systematic variation of causal effects across contexts. Here we show how the graphical language of causal diagrams...

The paper is a keynote lecture from the Tilburg-Madrid Conference on Hypothesis Tests: Foundations and Applications at the Universidad Nacional de Educación a Distancia (UNED) Madrid, Spain, 15-16 December 2011. It addresses the role of tests of statistical hypotheses (specification tests) in...

Trygve Haavelmo's The Probability Approach in Econometrics (1944) has been widely regarded as the foundation document of modern econometrics. Nevertheless, its significance has been interpreted in widely different ways. Some modern economists regard it as a blueprint for a provocative, but...

Trygve Haavelmo’s The Probability Approach in Econometrics (1944) has been widely regarded as the foundation document of modern econometrics. Nevertheless, its significance has been interpreted in widely different ways. Some modern economists regard it as a blueprint for a provocative, but...