Cross design synthesis : a new strategy for medical effectiveness research : report to Congressional requesters / United States General Accounting Office.

  • United States. General Accounting Office.
Date:
[1992]
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Licence: Public Domain Mark

Credit: Cross design synthesis : a new strategy for medical effectiveness research : report to Congressional requesters / United States General Accounting Office. Source: Wellcome Collection.

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    Objective, Approach, and Methodology Chapter 1 Introduction and Review of Study Designs for Evaluating Treatment Effectiveness the goal of the strategy presented here, which we term “cross design synthesis.” Our overall objective is to develop a strategy for cross design synthesis: specifically, a methodology for combining results from diverse, complementary studies that have evaluated a given treatment’s effect. The long-term goal of our work is to improve knowledge about the effectiveness of medical interventions and thus to enhance the development of valid practice guidelines. Specifically, by increasing the validity, the credibility, and the efficient dissemination of such information, the potential for successful medical practice guidelines in the United States is enhanced. Our approach is anchored in meta-analytic principles and techniques. However, a cross design synthesis is quite distinct from a traditional meta-analysis. Foremost among the differences is the fact that a cross design synthesis combines results from study designs that have complementary strengths and weaknesses, and it is specifically aimed at reaping the benefits of the studies’ diverse strengths, while minimizing the bias associated with each study. The spirit of such an effort is well described by Shadish, Cook, and Houts (1986, p. 43) in their discussion of quasi-experimentation (that is, imperfect designs) from a “critical multiplist perspective”: “From a critical multiplist perspective, ... [dealing with imperfect designs] ... resembles chess in several ways. Each chess piece has different strengths and weaknesses with respect to mobility and direction. Similarly, ... no two kinds of design or analysis are the same; each is associated with a unique set of biases. In chess, no single piece is capable of winning the game by itself. Rather, the best chance of winning occurs when all the pieces work together, using the strengths of each to protect against the weaknesses of the others.” As already noted, the challenge of cross design synthesis lies in the fact that one cannot expect the various design weaknesses (and consequent biases in study results) to cancel out one another. This makes any attempt to combine the results of different, complementary types of studies difficult: The different weaknesses associated with the different designs must be assessed according to a specific strategy and then taken into account when combining the results. In light of this, strategies for cross design synthesis must be based on the full set of methods that have been used to assess, adjust, and combine