Yep, the trick you posted should work well as long as you’re using 0 + Intercept syntax, rather than the implicitly centered design matrix that brms otherwise uses.

if I want the model to have no intercept (at the population-level, not just per “random effect”), I had been using -1 + but how would that syntax be combined with the 0 + Intercept syntax you propose ? would it be just 0 + ?

Pretty sure you should be fine then, but paging @paul.buerkner to be absolutely certain:

If the user excludes the intercept with -1 + ... does this turn off the design matrix centering in the same way as excluding the intercept with 0 + ...?

In the mean time @shira I’m confident you should get what you want if you replace your -1 + with 0 + , and just don’t include the special Intercept term.

In the brms formula documentation, it looks like the design-matrix centering is only for the population-level ? Would Z_is_not_0 in my above (-1 + Z_is_not_0 | Z) be centered, given that it is a group-level covariate ?