Nest Survival error

[nperlut]

Hi all, I am new to using the Nest Survival models and need some advice on an error. I am running models with covariates and get the following error. Some of the models seem to run but most do not:

WARNING Possibly invalid observation -- last 2 times not equal and fate=0.
WARNING Invalid observation -- all times same.
WARNING Invalid observation -- last 2 times equal and fate>0.

I have triple checked my inp file and I am pretty sure it parallels what is described in Ch 17. Any advice?
Thanks,

noah

[B.K. Sandercock]

Hi Noah:

First check your dates. If fate=0 (survived), the last two dates have to be the same. If fate=1 (failed), the last two dates have to be different and bracket the period of failure. If you truly know that a nest was both active and failed on the same day, you can backdate the last day active to the previous day. You can censor nests where all dates are the same, they have no exposure days that can be used in the the estimates. Convert them to a comment in your input file if you want to keep all of the info together: /* [nest info] */

If all of your dates look okay, then check to see that you have a column in your input file for a count of nests with each encounter history. Usually a column of ones if each row in the input file is a different nest. When a nest survival analysis chokes for me, it is usually because I have forgotten to include the frequency as a required column between the column for nest fate and any individual covariates.

Looking forward to seeing your new work.

Good luck, Brett.

[nperlut]

Thanks Brett!

noah