We derive a model for consumer loan default and credit card expenditure.The default model is based on statistical models for discrete choice, incontrast to the usual procedure of linear discriminant analysis. Themodel is then extended to incorporate the default probability in a modelof expected...

We explore practical methods of carrying out Lagrange Multiplier tests for variance components in two models in which the derivatives needed for the test are identically zero at the restricted estimates, the random effects probit model and the stochastic frontier model. The techniques are...

We consider the estimation of the usual Gravity model of trade, which involves flows of trade, say exports, from country i to country j in time period t. We suggest an easy-to-implement generalised method of moments estimator that avoids the issues associated with the usual fixed effects...

Obesity is a major risk factor for several diseases including diabetes, heart disease and stroke. Increasing rates of obesity internationally are set to cost health systems increasing resources. In the US a conservative estimate puts resources already spent on obesity at $120 billion annually....

Recent studies in econometrics and statistics include many applications of random parameter models. The underlying structural parameters in these models are often not directly informative about the statistical relationship of interest. As a result, standard significance tests of structural...

The most familiar fixed effects (FE) and random effects (RE) panel data treatments for count data were proposed by Hausman, Hall and Griliches (HHG) (1984). The Poisson FE model is particularly simple and is one of a small few known models in which the incidental parameters problem is, in fact,...

We consider a bivariate Poisson model that is based on the lognormal heterogeneity model. Two recent applications have used this model. We suggest that the correlation estimated in their model frameworks is an ambiguous measure of the correlation of the variables of interest, and may...

This study presents several extensions of the most familiar models for count data, the Poisson and negative binomial models. We develop an encompassing model for two well known variants of the negative binomial model (the NB1 and NB2 forms). We then propose some alternative approaches to the...

We derive a model for consumer loan default and credit card expenditure. The default model is based on statistical models for discrete choice, in contrast to the usual procedure of linear discriminant analysis. The model is then extended to incorporate the default probability in a model of...

We present several modifications of the Poisson and negative binomial models for count data to accommodate cases in which the number of zeros in the data exceed what would typically be predicted by either model. The excess zeros can masquerade as overdispersion. We present a new test procedure...