This survey article provides the first comprehensive assessment of the functioning of the Trade Policy Review Mechanism (TPRM), the central monitoring platform of the World Trade Organization (WTO), over the first 20 years of the WTO's existence (1995-2014). Building on two large new datasets, we assess the performance of the Mechanism along three dimensions: (1) members' participation rates in trade policy reviews (TPRs); (2) the coverage of trade flows through participation of states in relevant TPRs; and (3) the content of their input into the reviews.
Descriptively, we identify a very prominent increase in members' participation rates, but also a very high share of dyadic trade flows covered by the TPRs. In the most recent period, members accounting for up to 95 per cent of the imports into the reviewed state take part in the TPRs, on average.
We also argue that the Mechanism provides space for substantial critical reviewing of members' policies, especially in some areas such as agriculture. However, we also identify specific pitfalls of the Mechanism, especially in its excessive formalism and lack of interactive discussion.