Analyses of Large Scale Medical Survey Data and the Policy Evalutions in Japan

2014 Fiscal Year Final Research Report

• Project/Area Number: 24330067
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Economic statistics
• Research Institution: The University of Tokyo
• Principal Investigator: NAWATA Kazumitsu 東京大学, 工学(系)研究科(研究院), 教授 (00218067)
• Co-Investigator(Kenkyū-buntansha): KAWABUCHI Koichi 東京医科歯科大学, 医歯(薬)学総合研究科, 教授 (10308934) ; KONDO Akiko 東京女子医科大学, 看護学部, 准教授 (70555424)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 経済統計 / DPCデータ / 医療政策 / 医療経済 / 計量分析 / 白内障 / 糖尿病 / 在院日数

Outline of Final Research Achievements

In this research project, we analyzed the medical data. We first built a new database over one million patients so that we could use the DPC (Diagnostic Procedure Combination) data obtained from various hospitals. Next, we developed new estimation and testing methods for the Box-Cox transformation model (BC model). The BC model is usually estimated by the maximum likelihood estimator (BC MLE) assuming normality of error terms. However, the estimator is usually inconsistent. We proposed new consistent estimators by the modification of the likelihood function and Hausman type tests for the model. Using the newly developed database and estimation and testing methods, we then analyzed the length of stay (LOS) in a hospital for cataract and diabetes patients. To control the medical expenditure by reducing LOS is a very important issue in Japan. We found out that there were large differences in LOS among hospitals even after controlling types of diseases and characteristics of patients.

Free Research Field

経済統計