As a research fellow at the Sasakawa Peace Foundation USA from 2014 until March 2020, I developed a polling aggregator to track the Abe cabinet’s approval and disapproval ratings. With the arrival of Suga Yoshihide’s cabinet in September 2020, I want to once again aggregate Japan’s opinion polls so to provide a more accurate look at the prevailing government’s approval ratings.
My methodology is not particularly sophisticated. Current polls are averaged together, weighted by sample size. To adjust for the “staleness” of a poll, the sample size is adjusted according to an exponential decay formula. After ten days in the sample, a poll is removed, unless no new polls have appeared, in which case the sample size continues to be adjusted downwards until new polls appear.
I include the following polls in my sample: Kyodo News; Jiji Press; Yomiuri Shimbun; Asahi Shimbun; Nikkei Shimbun; Mainichi Shimbun; NHK; Asahi News Network. Like all polling aggregators, my hope is that by consolidating these polls, I am able to limit whatever biases are present in the individual polls and find a “truer” picture of the government’s support on any given day.