Strong theory, flexible methods: evaluating complex community-based initiatives.

A growing number of countries are beginning to move from acknowledging the existence of health inequalities to developing policies to reduce them. Many of these policies consist of complex interventions, operating at a number of levels, which aim to make a positive contribution to health improvement in deprived communities. Evaluating the efficacy of such initiatives poses particular challenges for evaluation. This paper argues that there is real potential in applying a theory-based approach to the evaluation of complex community-based initiatives. Using practical examples from the national evaluation of Health Action Zones in England, the paper outlines the key components of such an approach and argues that theory-based evaluation can strengthen programme design and implementation, as well as promote policy and practice learning about the most effective interventions for health improvement. We conclude that sophisticated theory building social change mechanisms in community settings is essential if real learning is to be generated from concerted efforts to achieve social change. [ABSTRACT FROM AUTHOR]