“Given the pluses and minuses of both approaches, we use the two approaches to complement one another. In particular, we obtain broadly similar results for IV and the PSM for a number of outcomes. For other outcomes, they look quite different. However, we are able to find sub-samples for whom OLSs look very similar to the IV results for the full population, and our selection of these sub-samples have a clear interpretation of being due to the difference between marginal and average cases.21 IV and PSM thus complement one another even in cases where they may appear at first blush to disagree.”