Sample selection versus two-part models revisited : the case of female smoking and drinking

There is a well-established debate between Heckman sample selection and two-part models in health econometrics, particularly when no obvious exclusion restrictions are available. Most of this debate has focussed on the application of these models to health care expenditure. This paper revisits
the debate in the context of female smoking and drinking, and evaluates the two approaches on three grounds: theoretical, practical and statistical. The two-part
model is generally favoured but it is stressed that this comparison should be
carried out on a case-by-case basis.