LIFETEST Procedure


The new SURVIVAL statement enables you to create confidence bands (also known as simultaneous confidence intervals) for the survivor function S ( t ) and to specify a transformation for computing the confidence bands and the pointwise confidence intervals. It contains the following options.

  • The OUT= option names the output SAS data set that contains survival estimates as in the OUTSURV= option in the PROC LIFETEST statement.

  • The CONFTYPE= option specifies the transformation applied to S ( t ) to obtain the pointwise confidence intervals and the confidence bands. Four transforms are available: the arcsine-square root transform, the complementary log-log transform, the logarithmic transform, and the logit transform.

  • The CONFBAND= option specifies the confidence bands to add to the OUT= data set. You can choose the equal precision confidence bands (Nair 1984), or the Hall-Wellner bands (Hall and Wellner 1980), or both.

  • The BANDMAX= option specifies the maximum time for the confidence bands.

  • The BANDMIN= option specifies the minimum time for the confidence bands.

  • The STDERR option adds the column of standard error of the estimated survivor function to the OUT= data set.

  • The ALPHA= option sets the confidence level for pointwise confidence intervals as well as the confidence bands.

9.1  

The LIFETEST procedure now provides additional tests for comparing two or more samples of survival data, including the Tarone-Ware test, Peto-Peto test, modified Peto-Peto test, and the Fleming-Harrington G family of tests. Trend tests for ordered alternatives can be requested . Also available are stratified tests for comparing survival function while adjusting for prognostic factors that affect the event rates.




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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