Acemoglu, Johnson, Robinson, and Yared (2008) demonstrate that estimation of the standard adjustment model with country-fixed and time-fixed effects removes the statistical significance of income as a causal factor of democracy. We argue that their empirical approach must produce insignificant...

Countries with the highest labor productivity overwhelmingly lie in the world's temperate climatic zones far away from the equator. The question we address is whether climatic conditions as measured by distance from the equator remain correlated with labor productivity after other variables are...