= Reference level in a regression factor
= Reference levels in a regression factor
{synonym}
= Reference level
{synonym}
With treatment coding, the intercept describes the reference factor level and each displayed factor coefficient is a contrast against that level. Changing the reference level reparametrizes the same fitted model: fitted probabilities and likelihood do not change, but coefficients representing different pairwise contrasts can have different standard errors and p-values.
Back to article page
