BICOP: a Stata command for fitting bivariate ordinal regressions with residual dependence characterised by a copula function and normal mixture marginals

Abstract

This article describes a new Stata command, bicop, for
fitting a model consisting of a pair of ordinal regressions with a flexible
residual distribution, with each marginal distribution specified as a two-part
normal mixture, and stochastic dependence governed by a choice of copula
functions. The bicop command generalizes the existing biprobit and bioprobit
commands which assume a bivariate normal residual distribution. The command and
post estimation options are presented and explained with an illustrative
application to data on financial wellbeing from the UK Understanding Society
Panel Survey.