Diverse methods can obviously complement and enrich each other, leading to better understanding and appreciation of the social and behavioral phenomena under investigation (Strange and Zyzanski, 1989). As discussed previously, the use of qualitative methods can provide insight into the meaning of quantitative findings at both the individual and system level.
While quantitative techniques can elucidate statistical significance, qualitative methods can reveal substantive significance. Similarly, quantitative methods can be used to improve the generalizability and inferential strength of findings from qualitative approaches.
Some years ago, New England Research Institutes conducted a traditional ethnographic study as an essential early component of a larger AIDS community intervention experiment (Smith et al., 1993). This study employed purposive sampling schemes, stratified in various ways to ensure the development of a picture of the whole community and to guard against the danger that the ethnographer would end up with informants who, while conveniently available, did not represent all groups of interest. Incidentally, this ethnography was not an afterthought, but actually served as the source of specific components of the subsequent intervention. In other words, it was the very foundation for the entire two-community experiment and informed the content of the pre- and -post-intervention surveys. The intervention that resulted from this ethnography proved to be the most effective field trial we ever conducted.
As applied to the area of health, behavioral and social science research needs to move from the level of de-contextualized individuals and rediscover the level of the social system (whole population approaches to health). Although tried and true quantitative methods generally work when the focus is limited to voluntary lifestyle changes at the individual level, they are not always useful or adaptable when the emphasis shifts to the whole population. Some techniques are misapplied, while others are inherently inappropriate.
The notion of "appropriate methodology" emphasizes the match between the level of intervention and the most suitable evaluation approach, with the choice of approach contingent on the problem, state of knowledge, availability of resources, audience, and so forth. There is no right or wrong methodological approach: appropriateness to the level and purpose must be our central concern.