マッチングアルゴリズムを活用した農地集約プログラム

黒阪健吾

東北学院大学 経済学部

with 小野寺直喜(一般社団法人Tannbo)

日本農業最大の問題点は、農家の耕作地が複数箇所に分散する、いわゆる「分散錯圃」（ぶんさんさくほ）にあります。農家の作業時間の10〜15%が圃場間の移動に充てられているという事例研究もあるなど、農地を集約することにより作業時間の短縮が期待できるほか、生産拠点の集約も可能となることから生産コストの減少が期待されます。しかしながら、わが国では農業所得の不安定さや農地の資産保有意識などにより農地の取引が活発に行われておらず、また、農地の貸し借りの調整も人の手で行われているという技術的な制約などから、地域の農業の担い手の農地面積を拡大すること（=農地の集積）や、農地の分散を解消すること（=農地の集約）は共に進んでいません。このような背景から本研究では、農家の耕作意向情報（「耕作したい農地」はどこか、「耕作したくない農地」はどこか）を専用Webアプリを通じて収集し、アルゴリズムを用いて「耕作したい農地」と「耕作したくない農地」をマッチングさせることにより、農家の意向が反映させた農地の集約案・集積案を作成するプログラムを開発しています。今回の発表では、令和４年度から６年度にわたって、岩手県盛岡市で実施した一連の実証実験の結果を紹介します。また、令和７年度から始まる、農地集約プログラムが農家の生産性に与える影響について検証するRCTの実験デザインを紹介します。

2025年04月16日(水) 12:00-13:00

永国寺キャンパス A327

On mechanism design under inferential naivety and learning from market history

室岡健志

大阪大学社会経済研究所

with 山下拓朗（大阪大学）

本報告では、限定合理的な戦略的思考の意味でのバイアスをもつ消費者と合理的な消費者が混在する場合における最適な市場メカニズム設計の分析を紹介する。具体的には、Eyster and Rabin (2005, Econometrica)で定義されている「相手プレイヤーが持つ私的情報を、その相手が取る行動から完全合理的に推測することができない（cursedness）」というバイアスに着目し、アカロフの中古車市場モデルのような片側の逆選択により市場の失敗が存在する場合における最適なメカニズム設計を理論的に分析する。加えて、バイアスをもつ消費者が過去の市場取引情報から財の価値について学習が可能な場合における市場設計について議論する。

2025年05月07日(水) 12:00-13:00

永国寺キャンパス A327

Public Media Do Serve the State: Evidence from a Randomized Experiment

黒田敏史

東京経済大学 経済学部

with 北村周平

This study examines the demand and supply of information in public media within democratic settings using natural language processing and a randomized experiment. By applying unsupervised machine learning to a corpus of approximately 200,000 TV programs, we find that public media tend to favor the government’s views over those of foreign governments. However, this bias does not extend to ideological divisions along partisan lines. To further explore the effects of public media exposure, we randomly increased access to public media programs. Participants in the treatment group evaluated government policies more favorably than those in the control group, suggesting that public media influences public opinion. Building on these findings, we develop a structural model that accounts for strategic interactions between broadcasters and conduct counterfactual simulations. In a counterfactual situation where all consumers were subjected to the same environment as the treatment group, equilibrium results indicate increased exposure to public media content, bringing it even closer to the government’s position. In contrast, reducing overall TV demand by half leads all broadcasters to produce more balanced information.

2025年05月21日(水) 12:00-13:00

永国寺キャンパス A327

Using Final Tax Return Data for Heterogeneous-Agent Dynamic General Equilibrium Model

Kazuki Hiraga

Graduate School of Economics, Nagoya City University

with Hiroshi Gunji (Daito Bunka University), Kenji Miyazaki (Hosei University)

We use novel Japanese final tax return (FTR) data to estimate both the progressive income tax function and income shock. We also study the macroeconomic and distributional implications of using them in the heterogeneous-agent macro model. Tax progressivity in the FTR data is low and almost flat regarding the tax function. Regarding the income shocks, the FTR data indicate that both the variance and persistence of income shocks are larger than the estimates based on Japanese survey data. The model calibrated based on the FTR data overestimates the income and asset inequality of the Japanese data but successfully replicates the consumption inequality.

2025年06月04日(水) 12:00-13:00

永国寺キャンパス A327

TBA

WEICHENG YI

Waseda University, Graduate School of Economics

2025年06月18日(水) 12:00-13:00

永国寺キャンパス A327

TBA

Vinh Pham

Graduate School of Economics, Waseda University

2025年07月02日(水) 12:00-13:00

永国寺キャンパス A327

TBA

Ruiqi TANG

Graduate School of Economics, Waseda University

2025年07月16日(水) 12:00-13:00

永国寺キャンパス A327

Nudge to Promote Bicycle Locking

Masako Oi

University of Kochi

with Takahito Shimada（Shiga University), Ryohei Hayashi (Kochi University of Technology), Kei Hibino (Kochi University), Nobuhiro Mifune (Kochi University of Technology), Hitomi Watanabe (Kochi University), Tomoko Yamakawa, Hideaki Kondo, Taiga Shindoi, Nozomi Tamura s(Community Safety Planning Division, Kochi Prefectural Police Headquarters)

Theft is a prevalent crime, particularly non-burglary and vehicle thefts, which account for a significant portion of reported cases. Many of these thefts can be prevented when victims take precautions, such as locking and securely storing their bicycles. In Kochi Prefecture in Japan, a staggering 79.28% of bicycle thefts involve unlocked bicycles, and using double locks can substantially reduce losses. We implemented a nudge to promote bicycle locking among junior and senior high school students to address this issue. Initially, we surveyed 3,806 junior and senior high school students in Kochi to understand their motivations for locking or failing to lock their bicycles in the school parking lots. We received valid responses from 1,188 students, resulting in a response rate of 31.21%. An analysis of these responses identified several factors influencing the decision to lock bicycles: the importance of bicycles, awareness of theft probability, habitual behavior, the influence of others locking their bikes, and long-term parking. Conversely, factors discouraging locking included perceived low effectiveness, theft awareness, inconvenience, lack of peer behavior, and short parking periods. Next, we employed a five-point Likert scale, ranging from 'I lock my bicycle every time' to 'I have never locked my bicycle,' as our dependent variable and performed regression analysis with each identified factor as an explanatory variable. Our findings revealed that the habit of locking was a significant reason for not locking, while the perception of hassle was a notable reason for not locking. We created posters encouraging students to lock their bicycles in response to these insights. We conducted a field experiment in which we displayed these posters in bicycle parking lots in different schools. Each poster featured one of three themes: one that emphasized the habitual nature of locking, another that addressed the inconvenience, and a third that encouraged locking. We visually measured the bicycle locking rates in the school lots before and after displaying the posters to assess the intervention's effectiveness. Ultimately, the results indicated no significant difference in locking rates between the different poster messages. However, analysis of a follow-up questionnaire revealed that schools where a higher percentage of students perceived locking their bicycles as habitual reported higher locking rates. In contrast, schools where students viewed locking as more troublesome had lower locking rates, aligning with our earlier factor analysis. Notably, when asked if they had seen the posters, only 19.46% of students confirmed they had, and many of those indicated they 'did not remember' the content. These findings suggest that at least two obstacles hinder the effectiveness of nudges. The first is whether the nudge influences behavior towards the desired action, and the second is whether it successfully reaches the target subjects. In this case, while the bicycle-locking promotion nudge aimed to guide students' behavior correctly, it ultimately failed to capture their attention and change their locking habits.

2025年08月06日(水) 12:00-13:00

永国寺キャンパス A327

TBA

後藤　晶

明治大学

TBA

永国寺キャンパス A327