random effects using lmer
HughSt <hughsturrock <at> hotmail.com> writes:
I am trying to run a logistic regression to look at the risk of malaria infection in individuals. I want to account for intra household correlation and so want to include a household level random effect. I have been using the lmer command in lme4 package but am getting some strange results that are completely different to those I get using STATA. Can I just check that this is the correct code lmer(IsPos ~ Dist + (1 | HouseID), family=binomial)
This does seem reasonable, although I would probably use glmer() rather than lmer() for clarity [lmer() automatically calls glmer() when 'family' is specified]
Where IsPos is a binary vector of positives and negatives, Dist is the variable of interest and HouseID is the household ID number. For those STATA users, the equivalent I'm using is xtlogit IsPos Dist, i(HouseID)
So you're not doing anything obviously silly. It seems that STATA uses gauss-hermite quadrature by default -- glmer uses Laplace, so you might try something like nAGQ=10 and see if anything changes. Follow-ups should go to r-sig-mixed-models <at> r-project.org