Green public procurement on EU directive 2014/24: adoption effects of mandatory and voluntary transposition

Abstract Regulation is one of the most crucial factors for implementing Green Public Procurement (GPP). This study provides the first multi-country causal analysis of GPP adoption using contract-level data, leveraging the transposition variability of the 2014/24/EU Directive. Using a Difference-in-Differences approach, the study examines the effects of mandatory and voluntary regulatory frameworks on GPP uptake, while accounting for the mediating role of bureaucratic quality. The results indicate that mandatory regulations significantly enhance GPP adoption; voluntary options can work in well-functioning administrations, but their effectiveness is strongly conditioned by bureaucratic quality, which in many specifications rivals or exceeds the direct effect of legal mandates. These findings underscore the critical interplay between institutional capacity and regulatory design, highlighting the need to tailor GPP policies to national institutional contexts to maximize their effectiveness.