Survival not recognizing right censored data

Question

I'm trying to run a survival analysis in R using the survival package. I have right-censored data only (time to event, then event "1" or censor "0"). I created a survival object using the Surv function. However, survdiff and coxph give errors, suggesting that they do not recognize it as right-censored data. Any advice?

> surv.dfs <- Surv(DaysFromTx,Event)
> surv.dfs
[1]   99:1  334:1 1024+  1341+   210+  1069+   890+  1242+   255+   228+   349+   300+   717+     2+   657+   995+   491+  1544+   265:1  440+   362:1  845+ 
[23]  669+  1176+   718+   768+  1171+  2276+  1152+   207+  1138+  1002+   942+   644+  1110+   179:1 1535+   841+   923+   904+   367:1  959+   746+  1256+ 
[45]   83:1  439:1   69+   449+   591+   983+   787+   704+   825+   747+    28+    41+   907+   181:1  371+   388+   166:1  702+   647+   944+   903+   797+ 
[67] 1095+   770:1 1118+    63:1 1762+  1662+   127:1  634+   312+   483+ 
> survdiff(surv.dfs ~ group)

Error in survdiff(surv.dfs ~ group) : Right censored data only

> coxph(surv.dfs ~ group)

Error in coxph(surv.dfs ~ group) : Cox model doesn't support "mright" survival data

Sapphira

Welcome to Stackoverflow. Can you please provide a reproducible R example? dput(surv.dfs) should help with that. – Adynamia

Answer 1

is your Event of a factor class? it should be numeric or boolean. so if your Event classes are 0 or 1, try:

df$Event <- as.numeric(df$Event)

Fourdrinier

Thank you, that worked. My event was classified as a factor. – Sapphira