On D. Schoenfeld's approach for testing the proportional hazards assumption

Abstract

A goodness-of-fit score statistic for the proportional hazards assumption is derived from a partial likelihood and is shown to be a simplification of Schoenfeld's (1980) statistic. In the case of the several group problem, the test statistic may be formulated as a simple sum of quadratic expressions; a conservative form is also given in this case.