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Abstract:
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Generalized pairwise comparisons extend the Mann-Whitney form of Wilcoxon's test, or Gehan's generalization of this test for two samples of (possibly censored) observation. The test uses all pairwise comparisons between two patients, one in the treatment arm and one in the control arm, in terms of one or several prioritized outcomes. Each pair favors treatment, control, or neither. The treatment benefit is the difference between the proportion of pairs in favor of treatment less the proportion of pairs in favor of control; this statistic is called the net chance of a better outcome. For a single variable, such as survival, the treatment benefit is the net chance of a longer survival. The pairwise comparison approach allows one to use a threshold of clinical relevance, say m months, and to estimate the net chance of a longer survival by at least m months. This feature is attractive in situations of non-proportional hazards, when interest focuses on late survival benefits, as is the case when testing immune therapies in oncology. The approach also allows several prioritized outcomes, for instance time to tumor progression and overall survival, to be analyzed simultaneously.
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