Cox Proportional Hazards Regression - Quick Tab

Select the Quick tab to access the options described below.

Input type

The three types of input available for this analysis are described below:

Type Description
Survival time, covariates, factors, censor This input type requires that there is a set of 1, 2, or 6 variables that denote survival time, a censoring variable that indicates if a case is complete or censored, and a list of predictor variables that can be either continuous (covariates) or categorical (factors).

This input type allows three ways to specify survival times:

  • Variable with survival times (e.g., number of weeks surviving)
  • two variables containing the start and end dates respectively
  • six variables containing dates. Specifically, these variables should contain the month (1 to 12), day (1 to 31), and year when the particular observation began (e.g., when the patient was admitted to the hospital), and the month, day, and year when the observation was terminated (due to death/failure or censoring, e.g., when a patient was dismissed from the hospital).
Survival time, covariates, factors, censor, time-dependent covariates This input type is the same as the previous type with one addition: time-dependent covariates can be specified. A time-dependent covariate is an explicit function of time, for example timedep = v2 * log(T_) -5.4. This option is useful for testing the viability of the proportionality assumption.
Counting process style of input (start, stop, censor, covariates, factors) This input type requires that a start and a stop variable are both specified to define survival time. The start variable defines when the subject enters the risk set, while the stop variable denotes when the subject leaves the risk set. This input type allows great flexibility by controlling exactly which subjects are in the risk set at a specific time.

Other options in the Quick tab are as follows:

Element Name Description
Variables Click this button to display a variable selection dialog box. Depending on the Input type selected, Statistica prompts you to either specify the variable(s) with the survival times or a start and stop variable specifying the entry and removal of the subject into the risk set, the censoring indicator, covariates, factors, and an optional strata variable
Code for complete responses In this field, enter the codes or text labels that were used in the censoring indicator variable to uniquely identify complete (uncensored) observations
Code for censored responses In this field, enter the codes or text labels that were used in the censoring indicator variable to uniquely identify incomplete (censored) observations
Factor codes Click this button to display the Specify codes dialog box, which is used to select the codes for the factors selected for inclusion in the analysis. The currently selected codes for each factor included in the analysis will be displayed in the corresponding edit fields
Customize Design Click this button to display the Define Custom Design dialog box, which contains options to select the specific effects that are to be included in the model
Strata codes Click this button to display the Select factor codes dialog box, which is used to select the codes for the strata variable selected for inclusion in the analysis. The currently selected codes for the strata variable included in the analysis will be displayed in the corresponding edit fields
Expression(s) Click this button to display the Define Time-Dependent Covariates/Expressions dialog box, where you can add or remove a time-dependent covariate to/from the design, or edit an existing time-dependent covariate.
Note: This button is available only when the Survival time, covariates, factors, censor, time-dependent covariates option button (see above) is selected
.