/* Logrank test for many group survival difference */
filename t01 url 'http://hedwig.mgh.harvard.edu/biostatistics/sites/default/files/public/education/tmp_sample_data.csv';
proc import file=t01 out=t01 dbms=csv replace;
run;
ods listing exclude ProductLimitEstimates;
proc lifetest data=t01 plots=(s);
time recurr_day*recurrence(0);
strata race / test=logrank;
run;
/********************************** ANNOTATED RESULTS **********************************/
The LIFETEST Procedure
Stratum 1: race = 1
Summary Statistics for Time Variable recurr_day
Quartile Estimates
Point 95% Confidence Interval
Percent Estimate Transform [Lower Upper)
75 314.000 LOGLOG 277.000 314.000
50 314.000 LOGLOG 277.000 314.000
25 277.000 LOGLOG 89.000 314.000
Mean Standard Error
268.454 19.390
The LIFETEST Procedure
Stratum 2: race = 2
Summary Statistics for Time Variable recurr_day
Quartile Estimates
Point 95% Confidence Interval
Percent Estimate Transform [Lower Upper)
75 . LOGLOG 273.000 .
50 283.000 LOGLOG 273.000 .
25 273.000 LOGLOG 67.000 283.000
Mean Standard Error
245.567 20.476
NOTE: The mean survival time and its standard error were underestimated because
the largest observation was censored and the estimation was restricted to
the largest event time.
The LIFETEST Procedure
Stratum 3: race = 3
Summary Statistics for Time Variable recurr_day
Quartile Estimates
Point 95% Confidence Interval
Percent Estimate Transform [Lower Upper)
75 275.000 LOGLOG . .
50 275.000 LOGLOG . .
25 275.000 LOGLOG . .
Mean Standard Error
275.000 .
Summary of the Number of Censored and Uncensored Values
Percent
Stratum race Total Failed Censored Censored
1 1 31 6 25 80.65
2 2 19 5 14 73.68
3 3 10 1 9 90.00
-------------------------------------------------------------------
Total 60 12 48 80.00
The LIFETEST Procedure
Testing Homogeneity of Survival Curves for recurr_day over Strata
Rank Statistics
race Log-Rank
1 -0.6017
2 1.1421
3 -0.5404
Covariance Matrix for the Log-Rank Statistics
race 1 2 3
1 2.71719 -1.96918 -0.74801
2 -1.96918 2.47956 -0.51038
3 -0.74801 -0.51038 1.25840
Test of Equality over Strata
Pr >
Test Chi-Square DF Chi-Square
Log-Rank 0.6069 2 0.7383a
