Statistics in medicine
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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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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.
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There has been a heightened awareness of the dangers of selection bias over the past two decades. Certainly coverage in statistical and 'statistics for medicine', and epidemiology textbooks have allocated pages to warn investigators and readers of investigations to be aware of its presence. ⋯ It is the intent of this paper to present examples of selection bias in a variety of areas which have resulted in misleading or entirely incorrect results. We hope to help make such research scientifically 'politically incorrect' to the degree that the scientific community 'just says no' to such studies, either proposed or reported.