Theory, Like Mist on Spectacles, Obscures Vision

This article reflects upon the choice of theory in theory-driven evaluation. While theory is helpful in focusing evaluators ’ attention and facilitating investigation, it also excludes evidence that does not fit within its framework. The argument is that evaluators need to be aware of all theories that may impinge upon a programme and to defend the theory of choice. They also need to be explicit about what may be excluded from their investigation. Governments aim at change at a macro-level, often using macro-theory, whereas evaluators often concerned with the implementation of programmes may use theory that is at a different, usually the micro-level. Theories at these two levels are not always compatible. The article briefly outlines the development of the theory-driven approach before focusing upon evaluation in health promotion as a case study to highlight the issues