摘要：The Patient Survey is a designated statistical survey conducted every three years with the objective of obtaining basic data on the current status of patients in medical institutions in Japan. One of the most important items in the report of this survey is the estimated number of patients with various diseases in each prefecture or secondary medical area. This paper shows that the amount of missing data has increased recently and has reduced the precision in the estimation of patient numbers. We propose to adopt variable weighting for ratio estimation dependent on the differences in the institutional sampling rate instead of the currently used constant weighting, as the proposed method can be adapted to take account of the increases in missing data. The proposed method can improve the precision in the estimation of patient numbers in most diseases, based on quantitative assessment conducted using the actual data from the 1996 and the 1999 Patient Survey.
关键词：nonresponse;number of patients;Patient Survey;ratio estimation;stratified random sampling;variable weighting
