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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    The Scope of Our Study Extending Patient Coverage Chapter 1 Introduction and Review of Study Designs for Evaluating Treatment Effectiveness optimal—forms of implementing the treatment, and a single outcome measure, that study can only tell a small part of the story. Such a study may be a poor guide for making many of the decisions required in medical practice. Certainly, an equally scientific study of the same treatment could yield very different results if it focused on different kinds of patients, implementations, and outcomes. Ideally, information that serves as a basis for setting medical practice guidelines would cover the complete effectiveness domain. Scientific studies have often omitted large portions of that domain. Thus, our review of study designs and our proposal for an improved evaluation strategy is aimed at feasible approaches for achieving greater coverage of that domain, while maximizing scientific rigor. In developing the proposed evaluation strategy, we decided to target the simultaneous achievement of scientific validity and extended coverage with respect to one of the three dimensions of the effectiveness domain: the patient/disease dimension. Thus, our study focuses on designs and strategies for evaluating treatment effectiveness across the full range of patients, assuming a constant treatment implementation and a single outcome criterion. The primary effectiveness question we deal with is: What is the average effect of the treatment, calculated across all patients for whom it is intended (or to whom it is applied in medical practice)? Cronbach (1982, p. 155) has emphasized that if a general treatment policy is selected on the basis of “what works best on average,” then the “average” for patients participating in a study should match the average for all patients to whom the general policy will apply. Related questions concern how effective the treatment is with respect to different patient subgroups. For example, does the treatment provide more or less benefit for patients with different severity of disease or for patients in different demographic groups? Such questions are important because, to the extent that different kinds of patients (for example, the elderly or the most severely ill) respond to a treatment differently than other kinds of patients do, this information should be given to clinicians