[R-sig-ME] Convergence Issue

[Alex Waldman]

Dear All,

I have a dataset with 119 individuals with information on the presence of lesions of various types (1,2,3) at various levels (1,2,3) and want to understand the effect of type and location on lesion presence. Therefore, I ran the following:

glmer.model<-glmer(LesionPresence ~ Location*Type + (1 | ID), data=lesion_proportion_staged_level, family="binomial")

Unfortunately, I ran into the following warning:

In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv, :
Model failed to converge with max|grad| = 0.048092 (tol = 0.002, component 1)

I'm quite new to running mixed models and even with some googling am still unsure why I am running into this issue? Any insight would be much appreciated. I am attaching the model output below and the input data in case that is helpful and do let me know if you need any additional information:
Generalized linear mixed model fit by maximum likelihood (Laplace Approximation) [
glmerMod]
Family: binomial  ( logit )
Formula: LesionPresence ~ Level * LesionType + (1 | ID)
   Data: lesion_proportion_staged_level

     AIC      BIC   logLik deviance df.resid
  1080.4   1129.2   -530.2   1060.4      962

Scaled residuals:
    Min      1Q  Median      3Q     Max
-1.6875 -0.5649 -0.3291  0.7170  4.2816

Random effects:
Groups Name        Variance Std.Dev.
ID     (Intercept) 1.519    1.232
Number of obs: 972, groups:  ID, 119

Fixed effects:
                   Estimate Std. Error z value Pr(>|z|)
(Intercept)         -1.6081     0.2966  -5.423 5.87e-08 ***
Level1              -0.6006     0.3900  -1.540 0.123600
Level2              -0.7270     0.4094  -1.776 0.075782 .
LesionType1          1.6362     0.3538   4.624 3.76e-06 ***
LesionType2          1.1659     0.3524   3.309 0.000938 ***
Level1:LesionType1  -0.3568     0.5022  -0.711 0.477379
Level2:LesionType1  -0.2015     0.5211  -0.387 0.698986
Level1:LesionType2   0.4030     0.5004   0.805 0.420607
Level2:LesionType2   0.1608     0.5229   0.308 0.758387
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Correlation of Fixed Effects:
            (Intr) Level1 Level2 LsnTy1 LsnTy2 L1:LT1 L2:LT1 L1:LT2
Level1      -0.603
Level2      -0.574  0.447
LesionType1 -0.703  0.498  0.475
LesionType2 -0.694  0.503  0.479  0.582
Lvl1:LsnTy1  0.480 -0.766 -0.339 -0.691 -0.400
Lvl2:LsnTy1  0.461 -0.344 -0.775 -0.665 -0.385  0.466
Lvl1:LsnTy2  0.468 -0.772 -0.344 -0.392 -0.692  0.598  0.268
Lvl2:LsnTy2  0.453 -0.344 -0.773 -0.379 -0.665  0.267  0.607  0.468
optimizer (Nelder_Mead) convergence code: 0 (OK)
Model failed to converge with max|grad| = 0.048092 (tol = 0.002, component 1)