Designing interventions in psychosocial research.

There is little guidance in the literature on how to design cost-effective interventions for preventing or treating psychosocial health care problems. Four sources of information are described for developing interventions that are based on a strong theoretical and empirical foundation: (1) an explicit theory for intervention, (2) supporting descriptive data, (3) an evaluation of possible intervention strategies that are consistent with the theory and the supporting data, and (4) focus groups to examine the feasibility and external validity of the intervention before formal testing.