Harrell, F.E.

regression predictor model change regression modeling modeling regression coef ficients patient signi selection eijkemans mj habbema jd number steyerberg ficant problem harrell fe jr signi ficant change regression analysis selection bias schemper m editor / journal prespeci fied model ficient study likelihood prespeci signi ficant effects data sets coef ficients analysis kemmler courvoisier harrell estimation event relevance epidemiol candidate predictors effect prespeci fied author combescure c heinze agoritsas t signi ficance editor perneger tv habbema e-mail address simulation schemper estimate method eijkeman data structure threshold structure letter 1.5 error nonconvergence prespeci fied models epidemiology likelihood ratio tests issue sas 9.2/ proc health erasmus mc van houwelingen hc subject measurement prediction solution university performance speci fic data speci fic issue signi ficant results 10.1016/ j.jclinepi .2011.06.013 regression modeling strategies