Measurement scale validation with brms

Hi everyone!

I’m really sorry, my questions may be a bit basic as I’m just starting to use brms, but sadly I wasn’t able to find a response on my own… I am currently trying to assess a new measurement scale psychometric properties in the context of Ecological Momentary Assessment.

I managed to design a three-level model to explain participants’ responses (observations within day within participants). However, I still struggle with two problems for which I could not find a response:

  • Is there a way to compute Mean-square item fit statistics to assess model fit?
  • I would like to check if items thresholds are well ordered. It seems like they are when I use the plot function, but would like to verify on item characteristic curves. Is there a way to plot such curves based on brms output?

Thank you so much for your help and for this great package!
Best wishes for the new year,