Program evaluation is a systematic method for collecting, analyzing, and using information to answer questions about projects, policies and programs, particularly about their effectiveness and efficiency. In both the public and private sectors, stakeholders often want to know whether the programs they are funding, implementing, voting for, receiving or objecting to are producing the intended effect. While program evaluation first focuses around this definition, important considerations often include how much the program costs per participant, how the program could be improved, whether the program is worthwhile, whether there are better alternatives, if there are unintended outcomes, and whether the program goals are appropriate and useful. Evaluators help to answer these questions, but the best way to answer the questions is for the evaluation to be a joint project between evaluators and stakeholders.
The process of evaluation is considered to be a relatively recent phenomenon. However, planned social evaluation has been documented as dating as far back as 2200 BC. Evaluation became particularly relevant in the U.S. in the 1960s during the period of the Great Society social programs associated with the Kennedy and Johnson administrations. Extraordinary sums were invested in social programs, but the impacts of these investments were largely unknown.
Program evaluations can involve both quantitative and qualitative methods of social research. People who do program evaluation come from many different backgrounds, such as sociology, psychology, economics, social work, and public policy. Some graduate schools also have specific training programs for program evaluation.
Program evaluation may be conducted at several stages during a program's lifetime. Each of these stages raises different questions to be answered by the evaluator, and correspondingly different evaluation approaches are needed. Rossi, Lipsey and Freeman (2004) suggest the following kinds of assessment, which may be appropriate at these different stages: