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From | Eleonora Paesen <eleonora.paesen@googlemail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Query re. stsplit and survival modelling |
Date | Thu, 13 Dec 2012 15:34:06 +0000 |
Hello, I am using a dataset that includes monthly observations concerning several variables. I have used stsplit in order to include time-varying variables into Cox proportional and Weibull hazard models. Before running the models I have made sure that all time-varying variables has been opportunely stsplitted. However I have not expanded the dataset in order to have person-month observations by using the following command line: stsplit time, at(1(1)n) where 'n' corresponds to the 'last observed exit t' obtained after stsetting the data. Does anyone could explain the value of the expansion of the data on a strictly monthly basis instead of 'splitted episodes' basis, whose length could be more than one month? How the coefficients obtained in the models runned on the two datasets differ? Is there a practical reason for splitting the data on a monthly basis? Running times increase enormously and I am not sure there is any gain by st-splitting the data in order to obtain person-months observations. Any help or suggestionson the matter would be greatly appreciated. Best, Eleonora * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/