The SURVEYPHREG procedure fits the Cox proportional hazards model to sample survey data. The procedure is similar to the PHREG procedure , except that it incorporates complex sample design information in the analysis. The proportional hazards regression coefficients are estimated by maximizing a partial pseudo-log-likelihood function that incorporates the sampling weights. PROC SURVEYPHREG provides design-based variance estimates, confidence intervals, and tests for the estimated regression coefficients. For more information about PROC SURVEYPHREG, see Chapter 113: The SURVEYPHREG Procedure.