Is R&D intensity stationary?

Our paper is now published in Applied Economics:
https://doi.org/10.1080/00036846.2022.2038776

This paper was written last year with Yifei Cai. It was a really nice experience to explore the links between innovation and macroeconomics. We find that R&D intensity is stationary in the G7 countries when we consider structural breaks with smooth functions, with the notable exception of the U.S. Thus, we do not reject the Schumpeterian growth theory. Our policy recommendation would be to invest in knowledge to sustain productivity growth.

You can find the preprint version, the abstract and the keywords in an older post:
https://www.jamelsaadaoui.com/fourier-df-unit-root-test-for-rd-intensity-of-g7-countries/

Follow this link to get a free online copy (limited to 50) of this article:
https://www.tandfonline.com/eprint/342I4Y44VYMYENDJDDF4/full?target=10.1080/00036846.2022.2038776

You can quote this article as:
Yifei Cai & Jamel Saadaoui (2022) Fourier DF unit root test for R&D intensity of G7 countries, Applied Economics, DOI: 10.1080/00036846.2022.2038776