Brenda Engel, one of PERG's founders, compared PERG's evaluation approach to the experience of listening to music: In judging the quality of a piece of music, the critic can't reasonably begin with an analysis of notes, themes, time, key, and so on... Rather, she must undergo total physical immersion in the music itself: listening, feeling, responding to, being in it. It is only then that she is able to apprehend meaning and can begin to make distinctions and analyze the components with a better sense of how they relate to the whole.
For evaluators, a broad understanding of the context in which the program exists provides the framework within which meaningful assessment of the implementation of the program can take place. An initial immersion in the whole provides the necessary context for the eventual understanding of the parts. Over the course of the evaluation, this broad understanding is constantly tested and revised as evaluators look at data collected in the field.
Knowing and being able to describe the context in which the project is occurring is the consequence of having extensive direct contact with the project and its environment. Such understanding results from observing a range of events and activities, collecting data from each group of participants, and studying documents relating to the overall project implementation. Evaluators examine all the collected data and analyze it in relation to the project's intentions, discussing the interplay between the environment and the project as a component of their evaluation reporting.