Carol Weiss did much to enhance the role of evaluation in her writings. Her work shows evaluators what affects their roles as they evaluate programs. Furthermore, her theory of change spells out the complexities involved in program evaluation. There are various processes involved in the evaluation of programs. The paper looks at some of the aspects that inform this process. Effective evaluation of programs can lead to improvement of programs and good delivery of projects in future. It is Weiss who stated that evaluation should have an influence on policy and practice. Amongst other themes explored here are the politics of evaluation as well as the crucial role of the evaluator within the complexity of evaluation of programs.