1996 Volume 23 Issue 1 Pages 20-27
Exit polls are now taking an important role in Election-Night broad-casting to project the final seats and analyze voter's choice on issues. NHK has done more than 180 exit polls by statistical methods since1993. In our sampling system, polling stations are sorted first by party strength and regional differences and then selected with a probability proportinal to size. We interview voters with a different interval set at each point with taking record of refusals. Interviewing are done for 6-7 hours except early morning, noon and evening assumed to cover about 70% of voters and not to make prediction worse. We weight targeted-interviewers to be proportion to real voters and calculate probability of candidate's win. Within the expected sampling error, past exit polls have shown mostly consitent‘ BIAS’ to specific party and candidates such as under-score for Communist Party. Refusals is a possible cause of BIAS, yet to be solved for improvement.