The construction of context-mechanisms-outcomes in realistic evaluation

Aim: To discuss the construction of context-mechanisms-outcomes (CMOs) developed as part of a realistic evaluation study of two aggression management training programmes.

Background: Realistic evaluation draws on theories and methods derived from the social sciences. It provides a distinctive account of the nature of programmes and how they work. Realistic evaluation is a form of evaluation that is driven by theory, and was based by Pawson and Tilley ( 1997 ) on the philosophy of critical realism. Critical realism is an important perspective in modern philosophy and social science, but it is largely absent in the field of healthcare research.

Review methods: This paper provides a critical discussion on the construction of CMOs as part of a realistic evaluation study.

Data sources: This paper draws on the personal experiences of the author in using realistic evaluation to evaluate training in aggression management.

Discussion: Realistic evaluation stresses four key linked concepts for explaining and understanding programmes: 'mechanism', 'context', 'outcome pattern' and 'context-mechanisms-outcomes (CMO) pattern configuration'. A CMO configuration is a proposition stating what it is about an initiative that works, for whom and in what circumstances. In this way, the effectiveness of the programme is understood, with an explanation of why the outcomes developed as they did and how the programme was able to react to underlying mechanisms and in what contexts. Therefore, a realistic evaluation researcher is not just inspecting outcomes to see if an initiative (implementation) works, but is analysing the outcomes to discover if the conjectured mechanism or context theories are confirmed. This analysis provides not only evidence of effectiveness, but also an explanation that helps to develop and improve the content and the targeting of future programmes.

Conclusion: The development of CMOs requires a great deal of skill on the part of the researcher and requires a flexibility of approach when collecting and analysing the data and in understanding the topic being investigated.

Implications for research/practice: Applications of realistic evaluation have focused largely on evaluating initiatives in the field of social policy and, more recently, social work practice. To date, however, there have been few published realistic evaluation studies within nursing; therefore this study is novel in its use of the methodology.