Although the past decade has witnessed a fair amount of experimentation with performance-based payment models, primarily P4P programs, we still know very little about how best to design and implement VBP programs to achieve stated goals and what constitutes a successful program. The published evidence regarding improvements in performance from the P4P experiments of the past decade is mixed (i.e., positive and null effects); where observed, improvements were typically modest

Many of the published studies evaluating the impact of P4P programs suffer from methodological weaknesses that make it hard to determine whether the VBP intervention had an effect above and beyond other changes (e.g., investment in quality improvement support, public reporting, health information technology [HIT] investments and support) that were simultaneously occurring to improve quality and restrain spending

The paucity of publicly available information regarding what constitutes a successful VBP program—that is, what VBP design features and other factors (i.e., characteristics of the providers, the health care market where the VBP program is implemented, and policy/regulatory environment) facilitate success in VBP—presents challenges for policymakers who seek to design VBP programs