Measuring Protection: Mission Impossible?

There seems to be some confusion between ‘openness’ and ‘protection’ measures in the international trade literature. The aim of this paper is to bring together the state of the art in quantifying trade policy measures and, for this reason, we focus on the extent of the protection granted by policies rather than on the degree of openness of the economy. Given the considerable amount of literature that deals with these issues, we will limit our review as follows. On the one hand, we focus on trade policies implemented at the border and therefore do not consider all the other possible public interventions influencing trade flows. On the other hand, we only take into account indexes that explicitly adopt a metric expressed in a ‘scalar aggregate’ (tariff‐ and quota‐equivalent measures, or an index in a closed interval). We distinguish between indexes that aggregate across products (same barrier for more products) and indexes that aggregate across instruments (more barriers for the same product). Finally, in order to classify the large number of indexes covered in our review, we propose a typology based on three categories: incidence, outcome and equivalence.