Comparing green productivity under convex and nonconvex technologies: Which is a robust approach consistent with energy structure?

Total factor productivity is used to explore the input–output efficiency of the economy and the driving factors behind economic growth. Although scholars have researched the total factor productivity approach, comparisons among different models in empirical research are rare and few scholars have focused on worldwide total factor productivity gains. Using convex and nonconvex technologies, this contribution investigates green productivity gains of 129 worldwide countries during 2000–2019 based on three popular productivity measures, namely, Luenberger–Hicks–Moorsteen indicator, Luenberger productivity indicator, and Malmquist–Luenberger index, respectively. Inspired by a metafrontier approach, we compare their productivity evolutions with the energy structure among 121 economies. A negative relationship is expected between the change in the proportion of fossil fuel energy consumption and green productivity. Our results show that the Luenberger–Hicks–Moorsteen productivity indicator under nonconvex technologies is a more convincing productivity measure when considering undesirable outputs in production technology.