Table 2 Statistical software
R/Splus © | SAS © | SPSS © | Stata © | |
|---|---|---|---|---|
Graphical checks | survfit function | lifetest procedure | Survt command | sts command |
Time-by-covariate interactions | programming required. | phreg procedure (definition of interactions)/test statement. | time program command (definition of interactions)/cox reg command. | tvc option/stcox command |
Scaled Schonfeld residuals | cox.zph function | phreg procedure/ressch option | Not directly available/programming required | stphtest command |
Cumulative residuals | Timereg/gof libraries/cum.residuals function | phreg procedure/assess statement/ph option | Not directly available/programming required | Not directly available/programming required |