Like the field of evaluation, the field of systems thinking shares the goal of describing and assessing programs or situations to recommend improvements and facilitate decision making. Pawson and Tilley’s acknowledgment of programs embedded in multiple social systems has gained little traction in realist synthesis and evaluation practice. A practice focusing on fairly closed systems—explaining how programs work and do not work—has emerged.

This article negotiates the boundaries of knowledge pertinent to have in program design and evaluation from a realist perspective. It highlights critical realism as another possible response to systems thinking in evaluation. Moving one level up a program, it theorises about social structures, mechanisms, and causes operating in a complex system within which an education-to-work program is nested. Three implications of the approach are highlighted: it foregrounds the relational nature of social, psychological, and programmatic structures and mechanisms; enables policymakers to develop a broader understanding of structures needed to support a program; and enables program architects to ascertain how a planned program might assimilate and adapt to social structures and mechanisms already established in a context.