Concern has intensified in recent years that many instrumental variables used in widely-cited growth regressions may be invalid, weak, or both. Attempts to remedy this general problem remain inadequate. We demonstrate that a range of published growth regressions may contain spurious results...

We show that when instruments are nearly exogenous, the two stage least squares t-statistic unpredictably over-rejects or under-rejects the null hypothesis that the endogenous regressor is insignificant and Anderson-Rubin test over-rejects the null. We prove that in the limit these tests are no...