[R-sig-ME] lmer and log link

[David Winsemius]

On Oct 31, 2012, at 11:18 AM, Hugh Sturrock wrote:

> 
> Hello all,
> 
> 
> 
> I am running a lmer model with two random effect levels, household nested in village, with two categorical predictors and a binomial outcome. I would like to obtain risk ratios and so am using the term family=binomial(link=log).

Couldn't you use Poisson errors with a log link. I would think that should give you risk ratios and be a canonical link-error pairing.

> However, using this link doesn‚t allow the model to converge properly and I get the following message:
> 
> 
> 
> Error in
> mer_finalize(ans) : 
> 
>  mu[i]
> must be in the range (0,1): mu = 18.3133, i = 166
> 
> 
> 
> As I understand it from posts elsewhere, this is due to the fact that one or more observations producing a linear predictor that, when mapped to a predicted probability, falls outside the admissible range of [0,1]. Does anyone know of a way to overcome this?Thank you!Hugh
> Hugh Sturrock 
> 
-- 

David Winsemius, MD
Alameda, CA, USA