Stata 11 help for st help st ------------------------------------------------------------------------------- Title [ST] st -- Survival-time data Description The term st refers to survival-time data and the commands -- most of which begin with the letters st -- for analyzing these data. If you have data on individual subjects with observations recording that this subject came under observation at time t0 and that later, at t1, a failure or censoring was observed, you have what we call survival-time data. If you have subject-specific data, with observations recording not a span of time, but measurements taken on the subject at that point in time, you have what we call a snapshot dataset; see [ST] snapspan. If you have data on populations, with observations recording the number of units under test at time t (subjects alive) and the number of subjects that failed or were lost because of censoring, you have what we call count-time data; see [ST] ct. The st commands are stset Declare data to be survival-time data stdescribe Describe survival-time data stsum Summarize survival-time data stvary Report whether variables vary over time stfill Fill in by carrying forward values of covariates stgen Generate variables reflecting entire histories stsplit Split time-span records stjoin Join time-span records stbase Form baseline dataset sts Generate, graph, list, and test the survivor and cumulative hazard functions stir Report incidence-rate comparison stci Confidence intervals for means and percentiles of survival time strate Tabulate failure rate stptime Calculate person-time stmh Calculate rate ratios with the Mantel-Haenszel method stmc Calculate rate ratios with the Mantel-Cox method stcox Fit Cox proportional hazards model estat concordance Calculate Harrell's C estat phtest Test Cox proportional-hazards assumption stphplot Graphically assess the Cox proportional-hazards assumption stcoxkm Graphically assess the Cox proportional-hazards assumption streg Fit parametric survival models stcurve Plot survivor, hazard, cumulative hazard, or cumulative incidence function stcrreg Fit competing-risks regression models stpower Sample-size, power, and effect-size determination for survival studies stpower cox Sample size, power, and effect size for the Cox proportional hazards model stpower exponential Sample size and power for the exponential test stpower logrank Sample size, power, and effect size for the log-rank test sttocc Convert survival-time data to case-control data sttoct Convert survival-time data to count-time data st_* Survival analysis subroutines for programmers The st commands are used for analyzing time-to-absorbing-event (single failure) data and for analyzing time-to-be-repeated-event (multiple failure) data. You begin an analysis by stsetting your data, which tells Stata the key survival-time variables; see [ST] stset. Once you have stset your data, you can use the other st commands. If you save your data after stsetting it, you will not have to stset it again in the future; Stata will remember. Also see Manual: [ST] st Help: [ST] stset; [ST] ct, [ST] snapspan, [ST] glossary