NONRESPONSE ADJUSTMENTS FOR ESTIMATES OF PROPORTIONS IN THE 2010 SURVEY ON STRATIFICATION AND SOCIAL PSYCHOLOGY

The main purpose of this study is to investigate influence of nonresponse in the “Interview Survey for Stratification and Social Psychology in 2010” (SSP-I2010 Survey). Now, social stratification is one of main research themes in the study of Japanese society, and the SSP-I2010 Survey provides basic data to study social stratification and people’s views on economic inequality in Japan. From a target sample of 3,500, approximately half (1,737) did not respond in the survey, thus nonresponse bias is a serious concern. From a survey methodological viewpoint, studies applying methods for dealing with nonresponse to Japanese surveys are few. Therefore many empirical studies with nonresponse bias adjustment are needed to understand influence of nonresponse in Japanese surveys. In an attempt to reduce the nonresponse bias in the SSP-I2010 Survey, we used two bias adjustment methods using information on both survey locations and individuals as auxiliary variables. The effectiveness of the bias adjustment methods was evaluated by a simulation and several items of the SSP-I2010 Survey where the values of population proportions are known. In this study, stratum identification was relatively insensitive to bias adjustment. On the other hand, the estimates of the proportion of people who accept the economic inequality increased by bias adjustment.