Overview (CSCOXREG command)

For samples drawn by complex sampling methods, CSCOXREG applies Cox proportional hazards regression to analysis of survival times—that is, the length of time before the occurrence of an event. CSCOXREG supports scale and categorical predictors, which can be time dependent. CSCOXREG provides an easy way of considering differences in subgroups as well as analyzing effects of a set of predictors. The procedure estimates variances by taking into account the sample design used to select the sample, including equal probability and probability proportional to size (PPS) methods and with replacement (WR) and without replacement (WOR) sampling procedures. Optionally, CSCOXREG performs analyses for a subpopulation.

Basic Specification

  • The basic specification is a variable list identifying the time variables (at least one but can be up to two), the factors (if any), and the covariates (if any); a VARIABLES subcommand specifying the event status variable; and a PLAN subcommand with the name of a complex sample analysis plan file, which may be generated by the CSPLAN procedure.
  • The default model includes main effects for any factors and any covariates.
  • The basic specification displays summary information about the sample and all analysis variables, model summary statistics, and Wald F tests for all model effects. Additional subcommands must be used for other output.
  • Minimum syntax is a time variable, a status variable, and the PLAN subcommand. This specification fits a baseline-only model.

Syntax Rules

  • The endtime variable, STATUS in VARIABLES subcommand, and PLAN subcommand are required. All other variables and subcommands are optional.
  • Multiple CUSTOM and PATTERN subcommands may be specified; each is treated independently. All other subcommands may be specified only once.
  • Empty subcommands are not allowed; all subcommands must be specified with options.
  • Each keyword may be specified only once within a subcommand.
  • Subcommand names and keywords must be spelled in full.
  • Equals signs (=) and slashes shown in the syntax chart are required.
  • Bold square brackets shown in the syntax chart are required parts of the syntax and are not used to indicate optional elements.
  • Subcommands may be specified in any order.
  • The factors, ID variable, baseline strata variable, and the subpopulation can be numeric or string variables, but covariates must be numeric.
  • Across the time variables, factor, and covariate variable lists, a variable may be specified only once.
  • The status variable, ID variable, baseline strata variable, and subpopulation variables may not be specified on the variable list
  • Minimum syntax is a time variable, a status variable, and the PLAN subcommand. This specification fits a baseline-only model.
  • Only factors and covariates can be defined by the TIME PROGRAM, all other variables cannot be defined there. See the topic TIME PROGRAM for more information.

Operations

  • TIME PROGRAM computes the values for time-dependent predictors (see TIME PROGRAM syntax help).
  • CSCOXREG performs Cox proportional hazards regression analysis for sampling designs supported by the CSPLAN and CSSELECT procedures.
  • The input dataset must contain the variables to be analyzed and variables related to the sampling design.
  • The complex sample analysis plan file provides an analysis plan based on the sampling design.
  • By default, CSCOXREG uses a model that includes main effects for any factors and any covariates.
  • Other effects, including interaction and nested effects, may be specified using the MODEL subcommand.
  • The default output for the specified model is summary information about the sample and all analysis variables, model summary statistics, and Wald F tests for all model effects.
  • This procedure uses the multithreaded options specified by SET THREADS.

Limitations

WEIGHT and SPLIT FILE settings are ignored with a warning by the CSCOXREG procedure.