Difference in differences methods have become very popular in applied work. These models are typically quite easy to implement and to interpret. However, performing inference with these models is not. This paper addresses one particular aspect that is likely to be very important in most...

This paper reports on a re-evaluation of the German health care reform of 1997. A previous evaluation found a limited effect of a 4.4 percent reduction of the number of doctor visits in a sample of pharmacy customers. The re-evaluation based on a representative household survey, the German...

In East Germany, active labour market policies (ALMPs) are used on a large scale to contain fast rising unemployment after unification. This paper evaluates the effects for participants in public employment programmes (PEPs), that are an important part of ALMPs. It focuses on individual...

Using data from Pennsylvania and New York and an array of empirical techniques to control for confounding factors, we recover hedonic estimates of property value impacts from shale gas development that vary with geographic scale, water source, well productivity, and visibility. Results indicate...