# right or interval censored survival curve for survival within a survey period

I was hoping somebody could help with a relatively easy survival analysis question.

I have survey data of an animal populaton and I want to create a survival curve for a specific year.

So, I have the age of the animal at the start of the year and the age of the animal at the end of the year and whether it died during that time period and what age that it died at.

I'm fairly new to survival curves and reading online examples it looks like I would need to do a right censored survival curve, to account for animals which have not died at the end of the year? Or would it be an interval censored curve, as I am taking readings between two points?

Many thanks for any pointers on this.

• If I understand correctly, you have 1.) Age at beginning of study 2.) Age at end of study 3.) Indicator of whether subjected died withing the study and 4.) If they died, the time of death. Is that correct? Jul 12, 2016 at 16:31
• Hi Cliff, that's correct.
– ALs
Jul 12, 2016 at 17:06

In your case, it sounds like you do not have interval censored data. This occurs with the event time is only known up to an interval. For example, suppose a mechanic examines a given part at times $t_1$, $t_2$. At $t_1$, the part is operational, but at $t_2$ the part is broken. Then all that is known is that the part is broken sometime in the interval $(t_1, t_2)$. However, in your case, the exact event time is either known exactly (subjected died in the study) or right censored (subject died before the study).