Extracting individual estimates for 2 factor models (ie. "3rd factor")

[joncybulski]

Hello,

I have a data set with 3 factors: Site, Sex, and ID (individuals). I want to run a model where I can get an estimate (4 food sources) for all three "groups", but I know that MixSIAR can only handle 2 factors (random and/or fixed).

I have compared various models using similar code to the alligator vignette, to find the best-fit model for my data.

My question is - once I have run the model (which should be SITE and SEX as random and fixed effects), is there a way for me to predict, or extract, an estimate of the INDIVIDUALS (the ID factor)? There is quite a good spread in my groups (site and sex), as these groups comprise ancient human populations. So, while understanding what the site was eating in general is great, I would also like to know what each individual was eating. I could run different models, but I feel this is statistically inappropriate, and my estimates from each model are obviously slightly different.

Image of the header of many consumer data.

Thank you!