This book analyzes the difficulties national government have had in attempting to link measurement of performance and results to the annual budget process. It is based on intensive reviews of four OECD countries that were early reformers and three pioneers in Central and Eastern Europe. In addition to looking at their current systems, the book looks at how their approaches have evolved over time. This book attempts to fill a gap between survey-based self-assessments and best-practice guides. It was compiled in response to the concerns of budget departments in countries in Eastern Europe and Central Asia, many of which are committed to adopting some form of performance-based budgeting and are seeking to learn from the experiences of previous reformers what the practical challenges are and how they can adapt best-practice approaches to messy reality. The case studies demonstrate a general pattern of disappointment with the results of performance budgeting, balanced by a strong belief in the underlying logic, which has resulted in repeated efforts to modify approaches to tighten the links between budgeting and performance. This has resulted in significant variation in how countries have implemented performance budgeting, as well as in the benefits they have derived. These variations offer guidance for models of next-generation performance budgeting by avoiding classic pitfalls that face repeat as well as new adopters and incorporating modifications introduced by those who have used it longest and found it at least somewhat useful.