On Thu, 27 Nov 2008, [EMAIL PROTECTED] went: > But neither control vs therapy comparison is even close to > significance by a chi-square test (e.g. Fisher´s exact), which means > either there´s nothing there, or not enough subjects were studied to > show it. > > So, what´s going on? Can Cox proportional hazards analysis > demonstrate something not evident by simple statistics?
My mostly intuitive response is that survival analysis is more sensitive than endpoint analysis because it accounts for every time point. In fact, when you do a survival analysis, you can use different types of significance tests to emphasize early differences in survival (that would be a Wilcoxon chi-square) or emphasize all time points equally (that would be a log-rank chi-square). I think the Cox model is more similar to the latter, but I'm a bit fuzzy on that. Either way, you're testing the whole pair of curves, not just the difference at the endpoint. So I think it makes sense for Anderson et al. to equate longer survival times with delayed mortality. As you noted, the Gigerenzer objection doesn't seem to apply here. --David Epstein [EMAIL PROTECTED] --- To make changes to your subscription contact: Bill Southerly ([EMAIL PROTECTED])
