Domestic revenue mobilization (DRM) has become an increasingly important part of international and country-level policy agendas. This Evaluation Insight Note gathers insights from World Bank projects and operations supporting DRM through a detailed review of six Independent Evaluation Group (IEG) Project Performance Assessment Reports (PPARs). It synthesizes key issues that affected each project's ability to sustain results across five countries (Croatia, Guatemala, Liberia, Pakistan, and Panama) and one state (Rio de Janeiro in Brazil). Interventions covered include four development policy operations (DPOs), one technical assistance loan, and one specific investment loan (now called investment project financing). Four insights from this synthesis are: 1) In the operations reviewed, political economy constraints were usually identified and analyzed at the time of approval and, for the most part, reasonable mitigation measures were identified ex ante
however, tax reforms were still derailed. 2) Prior actions in DPOs often benefited from being paired with investment projects or technical support from development partners. 3) Although coordinating with development partners was often discussed in project documents, extensive coordination occurred in only a few cases, with mixed results. 4) Results frameworks to track progress on DRM were often not well articulated, sometimes missing baselines or targets, being overly optimistic, or lacking clear results chains.