This chapter assesses the accuracy of procedural and bargaining models in predicting the outcomes of the reforms of the economic governance of the European Union that took place between 1997 and 2013. These negotiations addressed thirty-five controversial issues and were characterized by high costs of failure. How best should we understand the outcomes of these negotiations? Which factors best explain bargaining success? The chapter confirms the accuracy and robustness of the compromise model, based on country raw influence and the significance of preference centrality for bargaining success. However, a procedural model with a costly reference point performs well, indicating that misestimation of the no-agreement cost may be a reason for its commonly reported poorer accuracy. Procedural models are, however, more sensitive to measurement errors. The chapter also shows how both models contribute to understanding bargaining success and how the conditional influence of the European Parliament should not be ignored.