4 Mokyr (2014, p. 83) considers advances in research methods and tools and concludes that “the indirect effects  of science on productivity through the tools it provides scientific research may dwarf the direct effects in the long run." 5 David (1990) cautions that the effect of general-purpose technologies, such as electricity and electronic  computing, can take decades to fully unfold.
Brynjolfsson and Hitt (2000) consider the process followed by firms in leveraging innovations in IT equipment and emphasize the role of complementary investment in intangible assets like business reorganization. 6 Mohnen and Hall (2013) survey the empirical literature pointing to a link between R&D and productivity.