COMPARE Subcommand (SURVIVAL command)

COMPARE compares the survival experience of subgroups defined by the control variables. At least one first-order control variable is required for calculating comparisons.

  • When specified by itself, the COMPARE subcommand produces comparisons using the TABLE variable list.
  • Alternatively, specify the survival and control variables for the comparisons. Use the same syntax as used on the TABLE subcommand for specifying survival and control variables, omitting the value ranges. Only variables that appear on the TABLE subcommand can be listed on COMPARE, and their role as survival, first-order, and second-order control variables cannot be altered. The keyword TO can be used to refer to a group of variables, and the keyword ALL can be used to refer to an entire set of survival or control variables.
  • By default, COMPARE calculates exact comparisons between subgroups. Use the CALCULATE subcommand to obtain pairwise comparisons or approximate comparisons.

Example

SURVIVAL TABLE = MOSFREE BY TREATMNT(1,3)
  /STATUS = PRISON (1) FOR MOSFREE
  /INTERVAL = THRU 24 BY 3
  /COMPARE.
  • COMPARE computes the Wilcoxon (Gehan) statistic, degrees of freedom, and observed significance level for the hypothesis that the three survival curves based on the values of TREATMNT are identical.

Example

SURVIVAL TABLE=ONSSURV,RECSURV BY TREATMNT(1,3)
  /STATUS = RECURSIT(1,9) FOR RECSURV
  /STATUS = STATUS(3,4) FOR ONSSURV
  /INTERVAL = THRU 50 BY 5 THRU 100 BY 10
  /COMPARE = ONSSURV BY TREATMNT.
  • COMPARE requests a comparison of ONSSURV by TREATMNT. No comparison is made of RECSURV by TREATMNT.