In many contexts we may be interested in understanding whether direct connections between agents, such as declared friendships in a classroom or family links in a rural village, affect their outcomes. In this paper we review the literature studying econometric methods for the analysis of social...

It is increasingly common in empirical research to merge data sets containing different units of observation. When the units are not nested, a crosswalk specifying how the units from one data source are allocated to the units of the other is needed. Unfortunately, most crosswalks are ad hoc, a...

I derive the exact small sample properties of the instrumental variables estimator using a trigonometric approach. The distribution for the estimation error is decomposed into a product of three components - each with an intuitive interpretation. This approach helps the discussion on what...