Research

Selected manuscripts

Working Papers

Estimating the Partisan Bias of Japanese Legislative Redistricting Plans Using a Simulation Algorithm

(with Kento Yamada and Kosuke Imai)

Abstract

While partisan gerrymandering has been found to be widespread for Congressional redistricting in the United States, there exists little empirical research on legislative redistricting in other countries. We investigate the partisan bias of Japanese redistricting. Some scholars have argued that the prominent role played by the non-partisan commission leaves little room for partisan gerrymandering. Others have pointed out, however, that the Japanese redistricting process may be subject to political influence. The members of the redistricting commission must be appointed by the Prime Minister and be approved by the Diet. In addition, the commission invites the governors of all prefectures to provide their opinions regarding districting. We conduct a systematic empirical analysis to estimate the partisan bias of the 2022 Japanese Lower House redistricting plans. We apply a state-of-the-art redistricting simulation algorithm to generate a large number of alternative non-partisan redistricting plans. The sampled plans are representative of the population of plans and are consistent with the redistricting rules with which the commission must comply. By comparing the enacted plan with this non-partisan baseline, we quantify the extent to which the enacted plan favors a particular party. Unlike the traditional methods, our simulation approach accounts for political geography and redistricting rules specific to each prefecture. Our analysis shows that the Japanese redistricting process yields little partisan bias both at the prefecture and district levels.

BibTeX

@misc{
  author = {Miyazaki, Sho and Yamada, Kento and Imai, Kosuke},
  title = {Estimating the Partisan Bias of Japanese Legislative Redistricting Plans Using a Simulation Algorithm},
  doi = {https://doi.org/10.31235/osf.io/adxwt},
  url = {https://doi.org/10.31235/osf.io/adxwt}
  year = {2024}
}

Works in Progress

What Happens When Voters Can Delegate Their Votes? Evidence from Liquid Democracy Online

(with Andrew B. Hall)

Abstract

Since the 19th century, political reformers have proposed broadening voting in both civic and corporate governance by allowing voters to delegate their vote to others—sometimes known as liquid democracy. We provide the first empirical study of liquid democracy in a high-stakes, real-world setting, analyzing data from over 250,000 voters and 1,700 proposals across 18 voting communities, called “DAOs,” built on the Ethereum blockchain. We find that, on average, 17% of voting tokens are delegated, with substantial clumping on the most-popular delegates. Delegation is primarily bottom-up, with smaller token-holders more likely to delegate. More active voters receive more delegations, suggesting somewhat informed decision-making. Using a difference-in-differences design, we estimate that creating online hubs to coordinate delegation significantly increases delegation and overall voting rates. In sum, liquid democracy can foster bottom-up participation, particularly when paired with tools for coordination. On the other hand, real-world participation remains relatively low among both voters and delegates, posing an important challenge to liquid democracy not yet contemplated in existing theoretical literature.

Malapportionment for Gerrymandering: Exploring New Strategies of Electoral Manipulation with the Case of Malaysia

(with Chin-Huat Wong and Yuko Kasuya)

Abstract

Gerrymandering and malapportionment both undermine fair representation and involve electoral district boundaries. However, existing research has treated these phenomena separately, leading to disconnected bodies of literature. This paper aims to demonstrate that malapportionment can be an essential component of gerrymandering strategies, particularly when the ruling elites can control apportionment. In addition to conventional gerrymandering tactics of cracking and packing, the ruling party can employ a “self-crack” approach, adjusting district boundaries to increase their own seats without reducing the total number of opposition seats in a given region, such as the state or province. We illustrate this alternative strategy using the case of Malaysia, a long-lasting electoral authoritarian regime that endured from the early 1970s to 2018. By comparing the actual districting plan with counterfactual electoral districts simulated through Sequential Monte Carlo redistricting simulation, we identify significant ethnic gerrymandering against the minority Chinese Malaysians, in which self-cracking was one of the strategies adopted by the majority Malay-dominated ruling coalition.

Data

47-Prefecture Redistricting Simulations

(with Kento Yamada, Rei Yatsuhashi, and Kosuke Imai). 2022.

GitHub, Dataverse

Abstract

The goal of the 47-Prefecture Simulation Project is to generate and analyze redistricting plans for the single-member districts of the House of Representatives of Japan using a redistricting simulation algorithm. In this project, we analyzed the partisan bias of the 2022 redistricting for 25 prefectures subject to redistricting. Our simulations are designed to comply with the redistricting rules that the Council abides by.

This dataset contains sampled districting plans and accompanying summary statistics for the Japanese House of Representatives for the 25 prefectures subject to redistrict following the demographic shifts reflected in the 2020 Census, according to relevant legal requirements.

BibTeX

@misc{
  author = {Miyazaki, Sho and Yamada, Kento and Yatsuhashi, Rei and Imai, Kosuke},
  title = {47-Prefecture Redistricting Simulations},
  doi = {https://doi.org/10.7910/DVN/Z9UKSH},
  url = {https://doi.org/10.7910/DVN/Z9UKSH}
  year = {2022}
}

Other Writing

The Algorithms can resolve Japanese Electoral Malapportionment

(in Japanese, ‘Ippyo-no-kakusa’ wa saisentan no algorithm de kaizen dekiru).

(with Kento Yamada, Rei Yatsuhashi, and Kosuke Imai). 2022. Nikkei Business.

Abstract

We are invited to contribute to Nikkei Business, a Japanese business magazine. We show that the SMC redistricting simulation algorithm can be used to reduce malapportionment without splitting more municipalities, when compared to the districting plan proposed by the commission.

BibTeX

@misc{
  author = {Miyazaki, Sho and Yamada, Kento and Yatsuhashi, Rei and Imai, Kosuke},
  title = {The Algorithms can resolve Japanese Electoral Malapportionment (Ippyo-no-kakusa’ wa saisentan no algorithm de kaizen dekiru)},
  url = {https://business.nikkei.com/atcl/gen/19/00351/092100048/},
  year = {2022}
}

A Whale of a Tail: The Bank of Japan’s ETF Hoard

Part I and Part II

(with Nick Schmitz). 2021. Verdad Capital Research Library.

Abstract

• Part I: A case study on the impact of correlated ETF fund flows on stock price movements and what seems to have happened when the decade-long trend stopped.
• Part II: Measuring the impact of material, dynamic, and correlated ETF fund flows.

BibTeX

@misc{
  author = {Miyazaki, Sho and Schmitz, Nick},
  title = {A Whale of a Tail: The Bank of Japan's ETF Hoard},
  url = {https://verdadcap.com/archive/a-whale-of-a-tail-the-bank-of-japans-etf-hoard},
  year = {2021}
}