Abstract
Following the Fukushima Daiichi Nuclear Power Plant accident, individual external doses have been estimated by obtaining information on peopleʼs behavior at an initial stage after the accident and combining it with ambient dose rate maps. Residents in Fukushima Prefecture were asked to fill in their behaviors on self-administered questionnaires. The rate of response to the questionnaires was in the 20% range several months after sending out the questionnaire by mail. However, the rate did not subsequently increase by much after that, so various activities were taken to raise the response rate. Major activities were (1) creating a questionnaire that was simpler to fill out, (2) approaching Fukushima residents directly at various venues to help them fill out questionnaires, and (3) using the mass media to encourage people to submit questionnaires. While these activities, carried out primarily from FY2012 to FY2015, helped increase the number of responses, the response rate for the entire prefecture did not increase by much, and was at 27.6% as of March 31, 2018. However, rates exceeded 50% in most municipalities of the Soso region, where the damaged nuclear power plant is located. It appears that the response rate roughly reflected the ambient dose rate level.
