Identification of equations explaining a continuous variable, e.g., the length of sickness absence spells, by age, cohort and time (ACT), subject to their definitional identity is reconsidered. Various extensions of a linear equation to polynomials are explored. If no interactions between the...

We estimate the impact of climate change on agricultural production in a panel of 127 countries from 1961 to 2002. In contrast to the existing literature we account for cross-sectional dependence and technology heterogeneity. We find no significant impact of climate change on agricultural...