This paper examines the power of a conditional difference-in-differences approach to nonparametrically identify the causal effects of sequences of interventions. In the classical difference-in-differences case, a period previous to the implementation of the intervention is used as a comparison...

The assumption that the assignment to treatments is ignorable conditional on attributes plays an important role in the applied statistic and econometric evaluation literature. Another term for it is conditional independence assumption. This paper discusses identification when there are more than...