DEMAND FOR MEDICAL CARE BY THE ELDERLY: A FINITE MIXTURE APPROACH
用有限混合负二项计数模型分析老年人医疗需求，发现存在“健康”和“患病”两类潜在人群，模型优于标准负二项和障碍模型。
In this article we develop a finite mixture negative binomial count model that accommodates unobserved heterogeneity in an intuitive and analytically tractable manner. This model, the standard negative binomial model, and its hurdle extension are estimated for six measures of medical care demand by the elderly using a sample from the 1987 National Medical Expenditure Survey. The finite mixture model is preferred overall by statistical model selection criteria. Two points of support adequately describe the distribution of the unobserved heterogeneity, suggesting two latent populations, the 'healthy' and the 'ill' whose fitted distributions differ substantially from each other. © 1997 John Wiley & Sons, Ltd.