Narrow/correlated intercept pairs plot in ordinal model. A concern?

Interfaces brms
,
1

I am fitting a Graded Response Model (ordinal IRT) to evaluate a scale with several questions all using the same 7-point “agreement” scale. The model seems to fit well with no divergences and only a handful of k estimates > 0.7.

The model is:

fmla <- bf(Response ~ 1 + 
                            Factor + 
                            (1 + Factor |i| Question) + 
                            (0 + Factor | ID), 
                    disc ~ 1 + (1 + Factor |i| Question))

Factor is the result of a frequentist-based exploratory factor analysis using polychoric correlations between responses to 14 questions.

The pairs plot shows strong correlation between most of the intercepts, other then the last one.

Intercept_Pairs
Intercept_Pairs866×583 195 KB

Should I be concerned with the degree of correlation between the intercepts?

2

The correlations look to be on the high side, but I believe you’d expect high correlations among thresholds in an ordinal model.

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