STRATA Subcommand (COXREG command)

STRATA identifies a stratification variable. A different baseline survival function is computed for each stratum.

  • The only specification is the subcommand keyword with one, and only one, variable name.
  • If you have more than one stratification variable, create a new variable that corresponds to the combination of categories of the individual variables before invoking the COXREG command.
  • There is no limit to the number of levels for the strata variable.

Example

COXREG VARIABLES = SURVIVAL WITH GROUP
 /STATUS SURVSTA (1)
 /STRATA=LOCATION.
  • STRATA specifies LOCATION as the strata variable.
  • Different baseline survival functions are computed for each value of LOCATION.