IBM Water System SPSS COMPLEX SAMPLES 19 User Manual
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Chapter 12
Predictors
Figure 12-3
Cox Regression dialog box, Predictors tab
Cox Regression dialog box, Predictors tab
The Predictors tab allows you to specify the factors and covariates used to build model effects.
Factors.
Factors are categorical predictors; they can be numeric or string.
Covariates.
Covariates are scale predictors; they must be numeric.
Time-Dependent Predictors.
There are certain situations in which the proportional hazards
assumption does not hold. That is, hazard ratios change across time; the values of one (or more)
of your predictors are different at different time points. In such cases, you need to specify
time-dependent predictors.
of your predictors are different at different time points. In such cases, you need to specify
time-dependent predictors.
on p. 79.
Time-dependent predictors can be selected as factors or covariates.