This past year, Professor Kosuke Imai of the Department of Statistics and Government at Harvard University launched a research project to apply redistricting computational algorithms to Japan’s House of Representatives. With Reischauer Institute support, Prof. Imai was able to work with several Harvard undergraduates and a Keio University undergraduate. To date, they have completed analysis of 10 prefectures with the goal of expanding their analysis to all remaining prefectures in the near future and assessing the partisan bias of the newly enacted districting plans.

The initial results of the group’s analysis of their first 10 prefectures are publicly available at the project website of 47都道府県選挙区割シミュレーション. This website features a map of Japan that allows users to click on each prefecture and view each prefecture's results. The code and data used to produce these results are also publicly available on Harvard Dataverse, which allows other researchers to replicate and extend the project’s results. Prof. Imai and two undergraduate students, Kento Yamada (Harvard) and Sho Miyazaki (Keio), gave a poster presentation of the research at a conference of the Japanese Society of Quantitative Political Science, held at Waseda University in July 2022. Their poster can be viewed and downloaded below.

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