GAO presented information on evaluation synthesis, a systematic procedure for organizing findings from several disparate evaluation studies, which enables evaluators to gather results from different evaluation reports and to ask questions about the group of reports. The GAO evaluation synthesis guide presents information on: (1) defining evaluation synthesis and the steps in such synthesis; (2) strengths and limitations of evaluation synthesis; (3) techniques for developing a synthesis; (4) quantitative and nonquantitative approaches for performing the synthesis; (5) how evaluation synthesis can identify important interaction effects that single studies may not identify; and (6) study comparisons and problems.