-- this post authored by Marek Ignaszak and Petr Sedlacek To gauge the efficacy of policies aimed at spurring growth, we must first fully understand the sources of aggregate growth. This column argues that understanding the drivers of economic growth requires paying attention not only to productivity and R&D dynamics at the firm level, but also to changes in demand for firms’ products. The authors provide a new perspective on commonly used supply-side pro-growth policies and open the door to analysing demand-side policies such as public procurement or product market regulation, which have been present in the policy debate but have largely escaped academic circles.