R glmer warnings: model fails to converge / model is nearly unidentifiable -


i have seen questions on forum, , have asked myself in previous post still haven't been able solve problem. therefore trying again, formulating question can time, detailed information possible.

my data set has binomial dependent variable, 3 categorical fixed effects , 2 categorical random effects (item , subject). using mixed effects model using glmer. here entered in r:

modelall<- glmer(moodr ~ group*context*condition + (1|subject) + ``(1|item), data=rprodhsns, family="binomial")` 

i 2 warnings:

warning messages: 1: in checkconv(attr(opt, "derivs"), opt$par, ctrl = control$checkconv,  :   model failed converge max|grad| = 0.02081 (tol = 0.001, component 11) 2: in checkconv(attr(opt, "derivs"), opt$par, ctrl = control$checkconv,  :   model unidentifiable: large eigenvalue ratio - rescale variables?` 

my summary looks this:

generalized linear mixed model fit maximum likelihood (laplace approximation) ['glmermod'] family: binomial  ( logit ) formula: moodr ~ group * context * condition + (1 | subject) + (1 | item) data: rprodhsns`   aic      bic   loglik deviance df.resid 1400.0   1479.8   -686.0   1372.0     2195 `  scaled residuals:  min      1q  median      3q     max  -8.0346 -0.2827 -0.0152  0.2038 20.6578 `  random effects: groups  name        variance std.dev. item    (intercept) 1.475    1.215    subject (intercept) 1.900    1.378    number of obs: 2209, groups:  item, 54; subject, 45 fixed effects:` estimate std. error z value pr(>|z|)`                              (intercept)                -0.61448   42.93639  -0.014 0.988582   group1                     -1.29254   42.93612  -0.030 0.975984     context1                    0.09359   42.93587   0.002 0.998261    context2                   -0.77262    0.22894  -3.375 0.000739*** condition1                  4.99219   46.32672   0.108 0.914186 group1:context1            -0.17781   42.93585  -0.004 0.996696 group1:context2            -0.10551    0.09925  -1.063 0.287741 group1:condition1          -3.07516   46.32653  -0.066 0.947075 context1:condition1        -3.47541   46.32648  -0.075 0.940199 context2:condition1        -0.07293    0.22802  -0.320 0.749087 group1:context1:condition1  2.47882   46.32656   0.054 0.957328 group1:context2:condition1  0.30360    0.09900   3.067 0.002165 **  ---  signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 correlation of fixed effects:             (intr) group1 cntxt1 cntxt2 cndtn1 grp1:cnt1 grp1:2 grp1:cnd1 cnt1:1 cnt2:1 g1:1:1 group1      -1.000                                                                             context1    -1.000  1.000                                                                 context2     0.001  0.000 -0.001                                                               condition1  -0.297  0.297  0.297  0.000                                                        grp1:cntxt1  1.000 -1.000 -1.000  0.001 -0.297                                                 grp1:cntxt2  0.001  0.000  0.000 -0.123  0.000  0.000                                        grp1:cndtn1  0.297 -0.297 -0.297 -0.001 -1.000  0.297     0.000                                cntxt1:cnd1  0.297 -0.297 -0.297 -0.001 -1.000  0.297     0.001  1.000                         cntxt2:cnd1  0.000  0.000 -0.001  0.011  0.001  0.000    -0.197 -0.001    -0.001               grp1:cnt1:1 -0.297  0.297  0.297  0.001  1.000 -0.297    -0.001 -1.000    -1.000  0.001        grp1:cnt2:1  0.000  0.000  0.001 -0.198  0.000 -0.001     0.252  0.000     0.001 -0.136  0.000 

extremely high p-values, not seem possible.

in previous post read 1 of problems fixed increasing amount of iterations inserting following in command: glmercontrol(optimizer="bobyqa", optctrl = list(maxfun = 100000))

so that's did:

modelall<- glmer(moodr ~ group*context*condition + (1|subject) + (1|item), data=rprodhsns, family="binomial", glmercontrol(optimizer="bobyqa", optctrl = list(maxfun = 100000))) 

now, second warning gone, first 1 still there:

> warning message: in checkconv(attr(opt, "derivs"), opt$par, ctrl = control$checkconv,  :   model failed converge max|grad| = 0.005384 (tol = 0.001, component 7) 

the summary still looks odd:

generalized linear mixed model fit maximum likelihood (laplace approximation) ['glmermod']  family: binomial  ( logit ) formula: moodr ~ group * context * condition + (1 | subject) + (1 | item)    data: rprodhsns control: glmercontrol(optimizer = "bobyqa", optctrl = list(maxfun = 1e+05))`  aic      bic   loglik deviance df.resid  1400.0   1479.8   -686.0   1372.0     2195  scaled residuals:  min      1q  median      3q     max  -8.0334 -0.2827 -0.0152  0.2038 20.6610   random effects: groups  name        variance std.dev. item    (intercept) 1.474    1.214    subject (intercept) 1.901    1.379    number of obs: 2209, groups:  item, 54; subject, 45  fixed effects:                         estimate std. error z value pr(>|z|)     (intercept)                -0.64869   26.29368  -0.025 0.980317     group1                     -1.25835   26.29352  -0.048 0.961830     context1                    0.12772   26.29316   0.005 0.996124     context2                   -0.77265    0.22886  -3.376 0.000735 *** condition1                  4.97325   22.80050   0.218 0.827335     group1:context1            -0.21198   26.29303  -0.008 0.993567     group1:context2            -0.10552    0.09924  -1.063 0.287681     group1:condition1          -3.05629   22.80004  -0.134 0.893365     context1:condition1        -3.45656   22.80017  -0.152 0.879500     context2:condition1        -0.07305    0.22794  -0.320 0.748612     group1:context1:condition1  2.45996   22.80001   0.108 0.914081     group1:context2:condition1  0.30347    0.09899   3.066 0.002172 **   --- signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  correlation of fixed effects:         (intr) group1 cntxt1 cntxt2 cndtn1 grp1:cnt1 grp1:2 grp1:cnd1 cnt1:1 cnt2:1 g1:1:1 group1      -1.000                                                                             context1    -1.000  1.000                                                                      context2     0.000  0.000  0.000                                                               condition1   0.123 -0.123 -0.123 -0.001                                                        grp1:cntxt1  1.000 -1.000 -1.000  0.001  0.123                                                 grp1:cntxt2  0.001  0.000  0.000 -0.123  0.001  0.000                                          grp1:cndtn1 -0.123  0.123  0.123  0.000 -1.000 -0.123    -0.001                                cntxt1:cnd1 -0.123  0.123  0.123  0.000 -1.000 -0.123     0.000  1.000                         cntxt2:cnd1  0.000  0.000  0.000  0.011 -0.001  0.000    -0.197  0.001     0.001               grp1:cnt1:1  0.123 -0.123 -0.123  0.000  1.000  0.123     0.000 -1.000    -1.000 -0.001       grp1:cnt2:1  0.000 -0.001  0.001 -0.198  0.001 -0.001     0.252 -0.001     0.000 -0.136  0.000 

what can solve this? or can tell me warning means? (in way r-newbie myself can understand) appreciated!


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