Instrument policy mix and firm size: is there complementarity between R&D subsidies and R&D tax credits?

Nowadays, a rising number of evaluations investigates a multifaceted concept of the policy mix. Our study specifically focuses on the mix of two most frequently used supply-side instruments-R&D subsidies and R&D tax credits. Drawing on the longitudinal sample of Spanish manufacturing firms, we investigate whether there is a complementary interaction between these policy instruments with respect to product and process innovations. Moreover, by employing a dynamic random-effects probit estimator, we account for the persistence of innovation and endogeneity of public support. The results, that are separately estimated for SMEs and large firms, uniformly show evidence of no interplay between two policy instruments either in SMEs or large firms. However, among factors that influence the propensity to product and process innovations, by far, the largest effect is generated by true state dependence. These findings provide some policy implications for fostering product and process innovations in the long run.