Togaware DATA MINING
Desktop Survival Guide
by Graham Williams
Google

Regression

We might want to predict the time until event (e.g., death) for new observations. The function survreg can do this. A positive coefficient for an input variable means a longer survival time, which is usually a good outcome.

Or we might want to predict the death rate. The function coxph can do this. A positive coefficient for an input variable means a higher death rate, which is usually a bad outcome.

The different interpretations of the sign of the coefficient for the survreg model and the coxph model leads to some confusion. In the former, a positive coefficient is a good outcome and in the latter it is a bad outcome.

For either type of model the predict function can be used to obtain predictions.



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