The spontaneous theoreticians: How evaluators build and revise their knowledge of programs through experience

What exactly do evaluators learn about programs through experience and how? We chose a constructivist framework to investigate the structure of evaluators' program-related knowledge, namely the form, content, and origins of their expressed theories. In this context, we complemented a Piagetian theory of learning with new developments offered by ``probabilistic'' (or ``Bayesian'') models of learning. We conducted ``explicitation'' interviews with nine experienced practitioners, some specializing in the education or agri-environment sectors and some generalists. After examining the form and content of their program-related knowledge, we examine its development through experience but also through contact with researchers and readings. In conclusion, we discuss our study's strengths and limitations, as well as the implications of our results for evaluation training and teaching.