In this talk I discuss Pearson's X2 as a measure of goodness of fit for quantal response models, including binary outcome models (logit, probit, gompit), multinomial logistic regression (mlogit) and conditional logistic regression (clogit). Large sample results for X2 have been derived by a.o....

Testing for omitted variables should play an important part in specification analyses of statistical "linear form" models. Such omissions may comprise terms in variables that were included themselves (e.g., a quadratic term, or a categorical specification instead of a metric one), interactions...