I'm trying to fit a linear regression on a Poisson like outcome (lots of 0's and 1's and other integers) and currently trying to create log(y). However, R will return a list of numbers with lots of -Inf (log(0) = -inf).

I'm wondering how would make this model work by transforming the outcome variable (i.e. how other Poisson outcome linear regression models were fit)?

Please don't tell me that I should use a Poisson regression since I am. I'm trying to fit different models on the data and finding out which model performs the best.

  • $\begingroup$ I think that you're a little bit confused and flustered. I recommend taking some time away from your project to catch your breath. Once you get back, look up the poisson distribution -- it is defined on all non-negative integers. If you have 0/1 data, its binomial, rather than poisson. Consider reformulating your question to contain enough information for someone who knows nothing about your context to possibly help you. $\endgroup$ – generic_user Sep 28 '15 at 23:12
  • $\begingroup$ Are you getting at a glm with a poisson distribution but an identity link? $\endgroup$ – Matthew Drury Sep 28 '15 at 23:27
  • $\begingroup$ @generic_user I just said there are lots of 0's and 1's but also there are other numbers and I know how the distribution looks like. Just don't know how to log transform the outcome variable. $\endgroup$ – Yilun Zhang Sep 28 '15 at 23:46
  • $\begingroup$ @MatthewDrury One of the models is glm with poisson + log link but I didn't try the identity link, what is that for? $\endgroup$ – Yilun Zhang Sep 28 '15 at 23:46
  • $\begingroup$ It's an uncommon model, and I'm not sure if it's really for anything. I'm just trying to clarify what it is you're after, since you rejected classical poisson regression with a log link. $\endgroup$ – Matthew Drury Sep 28 '15 at 23:50

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