Did medieval and early modern guilds function primarily as institutions that fostered training, quality control and technological adaptation, or as monopolistic, rent-seeking cartels that restricted competition and innovation?

Historians continue to debate the economic impact of guilds: some regard them as monopolistic and rent-seeking, while others argue they facilitated training, quality control, and technological adaptation. Scholars associated with the rent-seeking reading (such as Sheilagh Ogilvie) stress guild regulation's anticompetitive effects, while scholars associated with the productive reading (such as S. R. Epstein) credit guilds with apprenticeship-based training, quality control and technological adaptation; the historiography has not settled between these readings.