Extensions of Differences in Differences (statistics) 1985 – 2011

The Difference-in-Differences (DiD) statistical method has now been in use for almost 30 years. see: ‘Using the Longitudinal Structure of Earnings to Estimate the Effect of Training Programs‘ by Orley Ashenfelter; David Card, The Review of Economics and Statistics, Vol. 67, No. 4. (Nov., 1985), pp. 648-660. (page 5 in the .pdf). And the Difference-in-Differences […]