Mixed-effects location-scale models in brms

[mike-lawrence]

FYI I’ve been engaged in ongoing work in this general domain:

• Computing ICC-like reliability (& within-unit variance) for hierarchical models? - #16 by mike-lawrence

• Feedback requested on possible subtle pathology of typical multivariate specification (or maybe bug?)

I’m working on validating the solution proposed in the latter now and hope to have that plus code implementing/validating the former done in the next month or so.