Medical Expense Variations and Standardization of Medical Treatments:Comparative Analysis Using the Receipt Data on Renal Failure, Hosoya Kei; Hayashi Yukinari; Kon-no Hiroki; Tokita Tadahiko, Iryo To Shakai, 12, 2, 121, 137, 2002, The Health Care Science Institute, In this paper, we use the claim data, which is based on the receipt of the National Health Insurance member, and clarify medical expense variations among both areas and medical institutions in three prefectures: Hokkaido, Chiba, and Fukuoka. The important problem, which is often pointed out in receipt-based medical studies, is the fact that there could be inconsistency between the disease name recorded in the receipt and the name of the disease actually affecting patients. Owing to this problem, we analyzed medical expense variations using renal failure data that is expected to resolve the inconsistency problem. Our main conclusions are listed below. (1) In full-sample analysis, we confirmed. medical expense variations among three prefectures for both inpatient and outpatient treatment. In particular, we captured obvious variations between the high medical expense area of Hokkaido and the lower one of Chiba. Moreover, as for outpatient treatmet in Fukuoka, we observed a possibility that treatments with low medical expense are excessively supplied compared with other prefectures. (2) When we concentrate our study on the institutions with high receipt, the clinical uniformity among medical institutions was observed simultaneously with low expense characteristics in Chiba. Therefore, some causality will be derived from this relationship. (3) From study on chronic renal failure in dialysis patients, it was clear that the standardization of the way of medical treatment would lead to the equality of medical expenses. This gives one active basis about the validity of DRGs/PPS.