On Wed, 31 Mar 2010, Parminder Mankoo wrote:
Hello All,
Does anyone know why length(fit1$time) < length(fit2$n) in survfit.coxph
output? Why is the predicted time length is not the same as the number of
samples (n)?
In fact it is not true that length(fit1$time) < length(fit2$n), since length(fit2$n)
is 1. Presumably you are asking why length(fit1$time) < fit2$n, or perhaps why
length(fit2$time) < fit2$n.
The reason is that fit2$time has entries for the unique times in the data set.
There are 241 records, but only 230 unique times. 10 times have two failures
and 1 time has a failure and a censoring.
As the documentation (?survfit.object) says
n total number of subjects in each curve.
time the time points at which the curve has a step.
-thomas
I tried: example(survfit.coxph).
Thanks,
parmee
fit2$n
[1] 241
fit2$time
[1] 0 31 32 60 61 152 153 174 273 277 362
365 499 517 518 547
[17] 566 638 700 760 791 792 809 822 845 944 1005
1077 1116 1125 1218 1369
[33] 1392 1400 1431 1492 1625 1642 1673 1674 1706 1766 1767
1795 1815 1826 1851 1857
[49] 2006 2010 2070 2084 2099 2121 2160 2191 2223 2230 2236
2314 2345 2400 2422 2434
[65] 2435 2495 2556 2557 2587 2588 2678 2802 2815 2833 2844
2860 2861 2910 2922 2953
[81] 2989 3010 3012 3014 3091 3167 3186 3226 3227 3242 3318
3346 3380 3448 3560 3561
[97] 3590 3773 3775 3805 3837 3895 3932 3943 3962 3987 4119
4139 4201 4206 4224 4232
[113] 4249 4321 4370 4453 4536 4539 4627 4656 4758 4763 4810
4939 4959 4962 5024 5047
[129] 5068 5088 5181 5216 5236 5308 5354 5384 5550 5757 5789
5796 5824 5917 5930 5934
[145] 6008 6025 6089 6117 6126 6143 6155 6209 6256 6349 6479
6607 6626 6642 6723 6760
[161] 6763 6789 6800 6878 6931 6970 7003 7065 7085 7093 7160
7184 7198 7247 7280 7288
[177] 7301 7364 7370 7381 7397 7410 7417 7470 7479 7519 7533
7545 7555 7668 7732 7736
[193] 7758 7807 7862 7867 7875 7884 7899 7911 7954 7958 7965
8006 8009 8023 8030 8080
[209] 8100 8133 8165 8308 8327 8381 8389 8569 8600 8697 8761
8806 8887 8961 9257 9510
[225] 9560 9598 9993 10122 10359 12457
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