Abstract
Weak instruments can produce biased IV estimators and hypothesis tests with large size distortions. But what, precisely, are weak instruments, and how does one detect them in practice? This paper proposes quantitative definitions of weak instruments based on the maximum IV estimator bias, or the maximumWald test size distortion, when there are multiple endogenous regressors.We tabulate critical values that enable using the first-stage F-statistic (or, when there are multiple endogenous regressors, the Cragg–Donald [1993] statistic) to test whether the given instruments are weak.
Original language | English (US) |
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Title of host publication | Identification and Inference for Econometric Models |
Subtitle of host publication | Essays in Honor of Thomas Rothenberg |
Publisher | Cambridge University Press |
Pages | 80-108 |
Number of pages | 29 |
ISBN (Electronic) | 9780511614491 |
ISBN (Print) | 9780521844413 |
DOIs | |
State | Published - Jan 1 2005 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- General Economics, Econometrics and Finance