Polling data
This data will be regularly updated and accessible to all subscribers. Check back for updates. Regular analysis of the findings of Japanese opinion polls is available here.
When I was a fellow at the Sasakawa Peace Foundation USA, I created a project called Japan Political Pulse, a ten-day weighted moving average of Japanese opinion polls that sought to reduce some of the noisiness around the different polls. When Ishiba Shigeru took office as prime minister in 2024, I revived the project, aggregating and averaging polls conducted by NHK, Kyodo News, Jiji Press, JNN, ANN, the Asahi Shimbun, the Yomiuri Shimbun, the Mainichi Shimbun, the Nikkei Shimbun, and Fuji TV-Sankei Shimbun.
Opinion polls included in the sample are adjusted using an exponential decay function over a ten-day period to account for “staleness.” Polls drop from the sample after ten days, unless there is only one poll in the sample and no new polls have been introduced. In this instance, the last poll will remain in the sample but will continue to “decay” until a new poll is introduced.
Japanese pollsters generally have fairly consistent biases in one direction or another, so I have worked on measuring pollster house effects and will likely adjust the averages for house effects going forward.
I estimated house effects of the polls included in my sample by taking simple averages of approval and disapproval ratings since the start of the Ishiba government and then calculating each pollster’s average deviations from these baselines.