Hi, This is a bit R unrelated, I want to, however, use my results from this in a R function. I am trying to figure out a formula for the deviance given a likelihood function. In my derivation I end up with having ln(y-1) twice in my expression for the deviance (see attached pdf). Which makes it impossible to calculate a value for the deviance since y can be = 1. I know this expression can be simplified differently avoiding ln(y-1). Does someone have a suggestion? I would appreciate you help very much! Thank you, Benjamin -------------- next part -------------- A non-text attachment was scrubbed... Name: deviance.pdf Type: application/pdf Size: 31482 bytes Desc: not available Url : https://stat.ethz.ch/pipermail/r-help/attachments/20070315/0e45be4f/attachment.pdf