Customizing the Kaplan-Meier Survival Plot
Hall-Wellner Confidence Bands and Homogeneity Test
You can use the following statements to add Hall-Wellner confidence bands (Hall and Wellner 1980) to Figure 23.1 and display the p-value from a test that the strata are homogeneous:
proc lifetest data=sashelp.BMT plots=survival(cb=hw test); time T * Status(0); strata Group; run;
The results are displayed in Figure 23.4. The Hall-Wellner confidence bands extend to the last event times. The small p-value supports rejecting the hypothesis that the groups are homogeneous.
Figure 23.4: Confidence Bands and Homogeneity Test

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