Program evaluation can be many things, like having a absolute understanding about things, analysis of a certain subject or might be a study of cause and effect of some topics.

According to this link,

https://methods.sagepub.com/reference/the-sage-encyclopedia-of-educational-research-measurement-and-evaluation/i16659.xml

Program evaluation refers to the systematic, scientific, and rigorous investigation of a program’s effectiveness. In education research, for example, such evaluations examine the goal attainment and outcomes of programs designed to promote student, teacher, and/or school performance. Through the evaluation of educational programs, the credibility and accountability of related education entities (i.e., curricula and educational services) and educational systems can be assessed and improved. This entry outlines the development of program evaluation, discusses some of the guidelines established for effective evaluation, and introduces three main approaches: quantitative design, qualitative design, and mixed-methods design.