This paper offers the first comprehensive quantitative explanatory study of the World Trade Organization (WTO) member states' activity in the Trade Policy Review Mechanism (TPRM), the WTO's central monitoring instrument. We analyze both the written questions submitted and the oral declarations delivered by the WTO members in all 95 trade policy reviews in the six-year period of 2009-2014.
Descriptively, we find that the European Union and the United States are the most active members, but that the so-called 'rising' powers - namely China, Brazil, and India - very closely follow. In addition, almost the entire membership is involved in reviewing activity, at least to some extent.
The explanatory results reveal that activity in the TPRM is strongly associated with a country's market size. However, the member states' overall aggregate membership in international organizations plays an almost equally important role.