A note on separated data and exact likelihood-ratio p-values in logistic regression

Abstract

Exact conditional p-values based on the likelihood-ratio statistic in logistic regression require accurate computation of the supremum of the likelihood function, particularly for outcomes in the sample space that represent completely-separated or quasi-completely-separated data sets. Current software does not always handle these cases well. Three simple solutions are proposed.

Keywords:

• Separation detection
• Exact conditional p-values