Statistics in medicine
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Statistics in medicine · Jul 1994
The relationship between clinical trials and clinical practice: the risks of underestimating its complexity.
Two main points are addressed in the following remarks. The first is that the survival of randomized clinical trials (RCTs) as the gold standard by which to assess the effectiveness of medical technology is being seriously challenged. ⋯ Contrary to what health services research has repeatedly indicated, trialists still, by and large, seem to believe in a simplistic model that assumes a one-way linear and rapid relationship between scientific knowledge and clinical practice. In the concluding section the paper pinpoints some issues to be further discussed from the point of view of monitoring and conducting trials.
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Statistics in medicine · Jul 1994
Comparative StudyData Monitoring Committees and early stopping guidelines: the Southwest Oncology Group experience.
Data Monitoring Committees in the Southwest Oncology Group comprise the study leadership and the leadership of the Group, augmented by some outside representation. The early stopping guidelines used by these committees are explicit in each protocol, and can be characterized as specifying a few interim analyses at conservative statistical levels. We describe our ten years of experience with this system, and give examples of different trials which have stopped either for positive or negative results.
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We propose and discuss several methods of monitoring multi-armed trials comparing means or survival. These methods combine multiple comparison procedures such as Fisher's LSD, Newman-Keuls and Tukey's with monitoring boundaries such as those of O'Brien and Fleming and Lan and DeMets. Tables of boundaries are provided for the equal variance or equal censoring distribution case.
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Statistics in medicine · Jul 1994
Some practical aspects of the interim monitoring of clinical trials.
The decision to stop accrual early to a clinical trial is often difficult and multifaceted. Interim monitoring boundaries have been found useful in U. ⋯ This paper also discusses rationale that lead to more conservative approaches to early stopping decisions than are currently employed. A recent initiative of the National Cancer Institute to achieve the objectives of independent data monitoring committees in the phase III clinical trials which it sponsors is also described.