PROC LIFEREG is used to fit a Weibull accelerated failure time (AFT…

Question

PROC LIFEREG is used to fit a Weibull accelerated failure time (AFT) model. How does PROC LIFEREG differ from PROC PHREG in its modeling approach?

Accepted Answer

PROC LIFEREG assumes a parametric distribution for survival time (e.g., Weibull, exponential, log-normal) and models log(survival time) as a linear function of covariates; PROC PHREG uses a semi-parametric Cox model with an unspecified baseline hazard — Here's the deal — b is correct because PROC LIFEREG fits parametric AFT models where the log of survival time is a linear function of predictors under an assumed distributional family (Weibull, exponential, log-normal, etc.). PROC PHREG fits the Cox proportional hazards model, which is semi-parametric: covariates enter multiplicatively on the hazard, and the baseline hazard is left unspecified.

Answer

PROC LIFEREG models the hazard ratio directly as a multiplicative function of covariates; PROC PHREG models survival time directly

Answer

PROC LIFEREG requires uncensored data; PROC PHREG handles right-censored observations

Answer

PROC LIFEREG computes the Kaplan-Meier curve; PROC PHREG extends it with covariate adjustment

PROC LIFEREG is used to fit a Weibull accelerated failure time (AFT) model. How does PROC LIFEREG differ from PROC PHREG in its modeling approach?

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