[R-meta] Meta analysis for identical multinomial logistic models

[Ricardo de Boer]

Dear community,

I was wondering if it is possible to use the metafor package for a
meta analysis on the results I achieved from multiple multinomial
models.
These multinomial models are all identical in the sense that they have
the same explanatory variables. The difference lies in the input data
that is used.
Every model has data from 1 individual, where the dataset varies much
in the amount of observations per model. The goal is to investigate
whether these individuals behave differently.

To be more precise, I am using baseball data per pitch from 2008-2019
to try and investigate if the strategies differ among pitchers and
which factors contribute to these differences.
The dependent variable is categorical with the values 'Fastball',
'Breakingball' and 'Changeup'.
For every pitcher, I ran the same multinomial model with fixed
effects. Just to name a few explanatory varaibles: count (factor
variable with amount of pitches and balls), the number of outs before
the pitch took place, if the pitcher is left/right handed.

At the moment, I have more than 2000 multinomial models where the
output summary is saved in a list.
Is it possible to use the package 'metafor' for my purpose? If so, how
would my next steps look like?
I have difficulty understanding how I would use the baseball data and
the output summary from my multinomial models with fixed effects
together with the metafor package.

Any assistance is much appreciated.

Ricardo