The length of stay and the effectiveness of medical treatment are analyzed using data from patients hospitalized for hip fractures in Japan. The influence of the Revision of the Medical Service Fee Schedule in April 2002 is evaluated, and factors which may affect the length of stay and the...

We analyze the length of hospital stays of patients hospitalized for cataract and related diseases (Diagnosis Related Groups (DRG) 2041) in Japan, utilizing the data pertaining to 3436 patients on whom one-eye lens operations are performed. We use the discrete-type proportional hazard model to...

The female labor supply models have been widely used in labor economics. The models are usually estimated by Heckman’s two-step estimator. However, Heckman’s two-step estimator often performs poorly. This paper considers an estimation of the models by the maximum likelihood method. An...

Hausman (1978) developed a widely-used model specification test that has passed the test of time. In this paper, we show that the asymptotic variance of the difference of the two estimators can be a singular matrix. Three illustrative examples are used, namely an exogeneity test for the linear...