Program Evaluation: The process of systematically gathering empirical data and contextual information about an intervention program — specifically answers to what, who, whether, and why question that will assist in assessing a program’s planning, implementation, and/or effectiveness (Chen, 2015, p.6)。

第2版の書籍（Practical Program Evaluation：Theory-driven evaluation and the integrated evaluation perspective by H. T. Chen, Sage，2015）における新たな定義。