Previous empirical studies on the impact of co-determination in innovations have yielded contradictory results: depending on the method and design, some report positive effects, others negative, and some find no effects at all. To find more substantiated answers, the authors of this volume have taken new approaches. They analyzed 46 more or less successful process innovations based on a theoretical framework that has proven effective in earlier innovation studies. Empirically, they relied on interviews with representatives from both the works council and management to illuminate the specific circumstances, as well as on quantitative methods of standardized questionnaire surveys to achieve the highest possible measurement quality. The results show that a stronger involvement of the works council increases both the economic and employee-related success of process innovations.