Conditional treatment is different to nested units as the levels are assumed to be distinct for the latter but not for the former.

## Arguments

- x
The name of the parent unit to nest under.

- ...
a single number OR a sequence of two-sided formula where the left-hand side corresponds to the name of the level (or the level number) of

`x`

and the right-hand side is an integer specifying the number of levels nested under the corresponding levels.

## Details

Currently when specifying conditional treatment, only character vectors are accepted on the RHS.

## See also

See `set_units()`

for examples of how to use this.