outliers in survival probability


New Member
Hi all,

We use survival data of 90 patients that were divided in two sub groups. (31, 59).
Two patients (out of the 31 sub group) survived 50% longer than all others.

Are they considered outliers? What are the criterions to define outliers?

Thanks for your help,
Or :D


TS Contributor
What criteria are you using? Survival data are rarely normally distributed. It is often highly skewed in either direction.


New Member
I personally don't recall ever hearing/reading talk of outliers in survival analyses. E.g., in this entire book chapter on Cox proportional hazards model the word "outlier" doesn't appear once