Knowledge that Transforms

THE SOCIETY’S MEMBERSHIP NUMBERS ARE PRESENTED in Table I, where the membership is classified according to institutional membership and individual membership. This year’s numbers confirm that the Society’s move to a “license” model has stopped and in fact inverted the longstanding decline in for institutional subscriptions. Individual membership has also increased, as it often does around years with a World Congress. All in all, our membership is up by close to one-quarter over 2015. Table II displays the division between print and online and online only memberships and subscriptions. Since the choice between these two alternatives was offered in 2004, there has been a continued shift toward online only. Many of the new institutional subscribers we reached with the license model have opted for an online subscription. On the other hand, individual membership numbers suggest that we may be close to a floor in print subscriptions at around 20% (and 10% for student members.) This remains to be confirmed. Table III compares the Society’s membership and the number of institutional subscribers with those of the American Economic Association. (For the membership category these figures include ordinary, student, free, and life members for both the ES and the AEA.) The ES/AEA ratio is at a record high level for institutional members; and it has returned close to its 2010 peak for individual subscriptions. The geographic distribution of ordinary and student members by countries and regions as of June 30 of the current and selected previous years is shown in Table IV. The table shows individual data on countries with more than 10 members in 2010. Our membership in Africa has been increasing fast. Several countries in Asia have also seen large increases, most spectacularly in China. On the other hand, it declined in the UK and in Germany. These changes are also apparent in Table V, which shows the percentage distribution of ordinary and student members by regions as of June 30 of the current and selected previous years. Finally, Table VI presents the percentage distribution of institutional subscribers by regions as of June 30 of the current and the previous four years. It shows that the increase in institutional membership this year is due to a remarkable recovery in the European region, where the trend had been negative for several years.

This paper notes a simple connection between synthetic control and online learning. Specifically, we recognize synthetic control as an instance of Follow‐The‐Leader (FTL). Standard results in online convex optimization then imply that, even when outcomes are chosen by an adversary, synthetic control predictions of counterfactual outcomes for the treated unit perform almost as well as an oracle weighted average of control units' outcomes. Synthetic control on differenced data performs almost as well as oracle weighted difference‐in‐differences, potentially making it an attractive choice in practice. We argue that this observation further supports the use of synthetic control estimators in comparative case studies.