Reverse causality in the R&D-patents relationship: an interpretation of the innovation persistence

Starting from the failure of the R&D-patents traditional relationship, when time-series and/or within-industry dimensions are included in the empirical analysis, the present work tries to contribute to the empirical literature from two directions. First, it performs a Granger causality test based on the theoretical presumption of a reverse patents→R&D link as an explanation for the failure of the traditional relationship. Second, assuming the reverse patents-R&D causality, we test and interpret the lag structure of such a relationship which shows the <italic>effective patent life</italic> that firms can expect within the two Schumpeterian patterns of innovations they belong to. In the light of the <italic>effective patent life</italic>, we offer a further explanation of innovation persistence which overturns the findings of the existing literature on persistence.