This article establishes a state of the art on the question of productivity. It first discusses the various definitions of productivity, and then examines the measures that have been suggested, with special attention to those proposed by Baayen. This survey leads to two results. The first is that the main recent developments do not concern the concept of productivity itself, but rather new measuring procedures which integrate both qualitative and quantitative aspects. The second is a significant increase in the importance of corpus-based studies in constructional morphology. Complex words are observed in situ in naturally occurring environments. Corpus-based studies allow one to distinguish active and inactive areas in a language, and to avoid confusing central and peripheral types of data.