Healthy aging: can clinical trials deliver?

The potential of a transdisciplinary research method - Quali-Quantitative Analysis (QQA) - for delivering better evidence for healthy aging is explored. Illustrative reviews from the literature on healthy aging are summarized, as are papers on methodology by Charles Ragin and colleagues. The evidence needs for healthy aging are explored, particularly in relation to the ability of randomized controlled trials (RCTs) to deliver rich, diversity-oriented evidence. The techniques of QQA, which involves treating cases as configurations, are described. The QQA method has potential value for healthy aging research in that: (a) it could provide evidence in combinatorial forms useful to holistic practice; (b) it could enrich the evidence for practice by providing more rigorous information from small-N groups, within RCTs and where RCTs cannot be used; and (c) it could add to the ability of RCTs to generate theoretical advances. © 2007 New York Academy of Sciences.