The ICPHREG procedure fits proportional hazards regression models to intervalcensored data. You can fit models that have a variety of configurations with respect to the baseline hazard function, including the piecewise constant model and the cubic spline model. PROC ICPHREG maximizes the full likelihood instead of the Cox partial likelihood to estimate the regression coefficients. Standard errors of the estimates are obtained by inverting the observed information matrix that is derived from the full likelihood. The following are highlights of the ICPHREG procedure's features:


For further details see the SAS/STAT User's Guide:
The ICPHREG Procedure
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