PHREG Procedure


The new WEIGHT statement enables you to specify case weights when you are using the BRESLOW or EFRON method for handling ties. Robust sandwich variance estimators of Binder (1992) are computed for the estimated regression parameters. You can specify the option NORMALIZE to normalize the weights so that they add up the actual sample size .

Two options have been added to the TEST statement: AVERAGE and E. The AVERAGE option enables you to compute a combined estimate of all the effects in the given TEST statement. This option gives you an easy way to carry out inferences of the common value of (say) the treatment effects had they been assumed equal. The E option specifies that the linear coefficients and constants be printed. When the AVERAGE option is specified along with the E option, the optimal weights of the average effect are also printed in the same tables as the coefficients.

The recurrence algorithm of Gail, Lubin, and Rubinstein (1981) for computing the exact discrete partial likelihood and its partial derivatives has been modified to use the logarithmic scale. This enables a much larger number of ties to be handled without the numeric problems of overflowing and underflowing.

9.1  

You can use the PHREG procedure to fit the rate/mean model for the recurrent events data and obtain prediction of the cumulative mean function for a given pattern of fixed covariates.

As an experimental feature, the PHREG procedure now can produce model assessments based on cumulative residuals.




SAS.STAT 9.1 Users Guide (Vol. 6)
SAS.STAT 9.1 Users Guide (Vol. 6)
ISBN: N/A
EAN: N/A
Year: 2004
Pages: 127

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