set_confidential_rr3() can only be used with
Poisson and binomial models (created with
mod_pois() and mod_binom().)
Random rounding to base 3 (RR3) is a confidentialization
technique that is sometimes applied by statistical
agencies. The procedure for randomly-rounding
an integer value \(n\) is as follows:
If \(n\) is divisible by 3, leave it unchanged
If dividing \(n\) by 3 leaves a remainder of 1, then
round down (subtract 1) with probability 2/3,
and round up (add 2) with probability 1/3.
If dividing \(n\) by 3 leaves a remainder of 1,
then round down (subtract 2)
with probability 1/3, and round up (add 1)
with probability 2/3.
If set_confidential_rr3() is applied to
a fitted model, set_confidential_rr3()
unfits
the model, deleting existing estimates.