This report is a self-evaluation of the Operations Evaluation Department's (OED) Country Assistance Evaluations (CAEs). CAEs examine World Bank performance in a particular country, usually over the past four to five years, and report on its conformity with the relevant Bank Country Assistance Strategy (CAS) and on the overall effectiveness of the specific CAS. This Retrospective addresses the question 'What Have We Learned?' by compiling lessons relevant for developing country assistance strategies from the most recent batch of CAEs. Second, it assesses revisions to the CAE process, methodology, and presentation to answer the question How Can the CAE Instrument Be Improved?