[R-sig-ME] lme4/glmer convergence warnings

[Corey Sparks]

Hello all,
I’ve been seeing the aforementioned convergence errors for weeks in a course i’m teaching using lme4, so I decided to follow Ben’s advice on reporting the :

I’m fitting a binomial GLMM for small area estimation model building here:
glmer(I(bmi>30)~povz+vachousz+baccz+blackz+hispanicz+factor(region)+(1|state)+(1|cofips), family="binomial", data=merged, weights=cntywt/mean(cntywt))

n=~240000, n_cofips=217, n_state=46
I get the warning:
In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
  Model failed to converge with max|grad| = 0.235915 (tol = 0.001)

and the gradients:

relgrad <- with(fit.1 at optinfo$derivs,solve(Hessian,gradient))
> max(abs(relgrad))
[1] 0.0001631008

and when I use refit(), I get:
fit.1<-refit(fit.1)
> relgrad <- with(fit.1 at optinfo$derivs,solve(Hessian,gradient))
> max(abs(relgrad))
[1] 2.369877e-06

For another model on a LMM, I get:

fit.mix<-lmer(bmiz~agez+lths+coll+black+hispanic+other+(1|cofips), brfss_11)

In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
  Model failed to converge with max|grad| = 0.00550412 (tol = 0.002)

relgrad <- with(fit.mix at optinfo$derivs,solve(Hessian,gradient))
> max(abs(relgrad))
[1] 8.099289e-08

Hope this helps


Corey Sparks
Assistant Professor
Department of Demography
The University of Texas at San Antonio
501 West Cesar E Chavez Blvd
corey.sparks 'at' utsa.edu
coreysparks.weebly.com
210 458 3166