RESUMEN
The need to promote healthy active ageing in order to offset the impact of an ageing population on national resources and ensure a high quality of life in older age is well recognized. In 2001, the English Department of Health established a national pre-retirement health initiative involving the development of eight pilot projects. A national evaluation using a 'theories of change' approach embedded within a realistic evaluation design was commissioned to draw out the lessons from across the projects. In this article we describe the methods used to identify and test out the projects' theories of change, and the results obtained. The theories of change identified revolved mainly around engaging clients and empowering them to take action through the provision of information. Two projects also saw providing opportunities for social interaction as a means to engaging and empowering clients. Theory testing indicated that health improvement services could be effectively targeted at people in mid-life and that service settings and style played an important part in engagement. In particular contexts, combining free health checks with financial advice was a significant motivator for engagement, as was perceived health need in two deprived areas. Gains in knowledge were also important for empowerment in some contexts, but validation of existing knowledge could be more important in others. Opportunities to engage in social activities were a potent mechanism for empowerment amongst women living in two deprived areas. Further work is required to test these conclusions in other contexts, and to ascertain how people from minority ethnic groups and men, particularly those outside the labour market, can be engaged in health improvement initiatives.