Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
In a recent contribution to the AER, Koopman, Wang, and Wei (2014) proposed a decomposition of a country's gross exports into value-added components and double-counted terms. It is motivated by complex manipulation of basic accounting identities. In this comment we provide an alternative framework based on "hypothetical extraction." This parsimonious approach provides a clear definition of domestic value added in exports and has a natural extension into decompositions of bilateral export flows.