tended, had elements that did not target behaviors properly. This pattern of evidence, with the contribution of different studies with different forms of measurement, may suggest that while the program was utilized, the intended effect was not observed. Ideally, these results can be obtained early enough to focus data collection toward the factors that might be related to such a finding.
In other words, if certain conditions are met, then it is possible to probe the plausibility that the intervention was responsible, at least in part, for the observed outcomes. As empirical evidence or assessments are repeated, the plausibility increases. Through multiple assessments, involving a logical network of evidence, it may be possible to derive a portrait of the plausibility. While there is a pool of studies of varying quality, the pattern of evidence approach requires at least some higher-quality studies (i.e., prospectively collected data) within the total pool of studies to be available to assess whether the evidence from the lower-quality studies is meaningful. This approach is particularly appropriate as an inferential strategy in the situation in which the number of any single type of studies (e.g., behavioral surveys, incidence data, surveillance data) is limited, precluding a preponderance of evidence approach. This pattern of evidence approach is not novel; it was described and used in a recent report that investigated the role of sterile syringes and bleach disinfection in HIV prevention (National Research Council, 1995).
This report reviews the literature on musculoskeletal disorders in the workplace, drawing on studies from basic sciences, epidemiology, and intervention research. Each of these types of research is reviewed separately in different chapters. However, there is also cross-referencing between chapters, and an integration chapter, to assemble inferences that are based on patterns of evidence about the associations that lead to the conclusions and recommendations in this report.