NBThetaBoundWarning

exception superglm.NBThetaBoundWarning

Bases: UserWarning

The NB2 theta estimate sits on an active search bound.

The reported theta_hat is the constrained boundary value, not an interior maximum-likelihood estimate, and the accompanying result carries converged=False. An active upper bound usually means the data are no more dispersed than Poisson at the fitted mean (the profile likelihood increases toward the Poisson limit theta -> inf); an active lower bound means overdispersion beyond the searchable range.