Using theory-based evaluation to build evidence-based health and social care policy and practice

Building an evidence base to underpin policy and practice in health and social care is one of the cornerstones of New Labour's modernization programme. However, the history of evaluation research in Britain and America suggests that this enterprise may be thwarted as much by politics as by methodological debates. The 'paradigm wars' that characterize the social sciences also feature in the field of evaluation research, and changes in the way 'health' is conceptualized in the 'new public health' have intensified debates about approaches to evaluation and what counts as evidence. Health Action Zones have been vaunted as both the 'flagships' of the government's health policy and as 'learning initiatives'. This paper uses the example of Health Action Zones to discuss the use of a theory-based approach to evaluation for the purpose of generating the policy learning needed to tackle health inequalities, drawing on experience in Plymouth. The limitations of the 'traditional' approach to evaluation are examined, along with recent guidance from the Medical Research Council about evaluating complex community initiatives. It is argued that the case for theory-based evaluation extends beyond criticism of the traditional approach to develop evaluation theory and practice from the perspective of critical realism. This approach to evaluation seeks explanation and understanding about how and why projects 'work' or not in specific contexts, rather than pragmatic solutions to de-contextualized problems. The paper concludes by reflecting on the politics of evaluation in the field of health and social care, calling into question the government's commitment to evidence-based policy and practice