What Belongs Where? Variable Selection for Zero-Inflated Count Models with an Application to the Demand for Health Care

This paper develops stochastic search variable selection (SSVS) for zero-inflated count models which are commonly used in health economics. This allows for either model averaging or model selection in situations with many potential regressors. The proposed techniques are applied to a data set from Germany considering the demand for health care. A package for the free statistical software environment R is provided.

Eye Care Service in Scotland: Did the Scots Get it Right?

In March 2004, the Scottish government announced a review of eye care services in Scotland, which culminated in the introduction of free eye examinations from 1st April 2006. This free eye examination is not just a sight test; it is a thorough examination to check the health of the patient’s eyes and to look for signs of other health problems. The Scottish government commissioned private ophthalmic optician practices to perform these eye examinations. Consequently, since April 2006 individuals in Scotland could walk into any high street optometry practice and get a ‘free’ eye examination funded under the NHS.

Estimating the Impact on Efficiency of the Adoption of a Voluntary Environmental Standard: An Empirical Study of the Global Copper Mining Industry

This paper uses data on the world's copper mining industry to measure the impact on efficiency of the adoption of the ISO 14001 environmental standard. Anecdotal and case study literature suggests that firms are motivated to adopt this standard so as to achieve greater efficiency through changes in operating procedures and processes. Using plant level panel data from 1992-2007 on most of the world's industrial copper mines, the study uses stochastic frontier methods to investigate the effects of ISO adoption. The variety of models used in this study find that adoption either tends to improve efficiency or has no impact on efficiency, but no evidence is found that ISO adoption decreases efficiency.