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ミクロ理論ワークショップ 2024
Microeconomic Theory Workshop
お知らせ2024年6月11日より、ミクロ理論ワークショップは、日本経済国際共同センター（CIRJE）が運営する体制から、野田俊也研究室がロジスティクスを担当し、UTMDとERATO小島マーケットデザインプロジェクトがサポートする体制に移管します。 ・これに伴い、Zoomリンクが変更となります。2024年5月30日以前にオンライン参加のためのZoomの事前登録をしていただいた方も、再度、新しいフォームでの事前登録をお願いします。 ・詳細はこちらから NoticeStarting on June 11, 2024, Shunya Noda's Lab will organize the microeconomic theory workshop, with support from UTMD and the ERATO Kojima Market Design Project, taking over logistics from the Center for International Research on the Japanese Economy (CIRJE). - We will use a new Zoom meeting room from June 11. If you registered for online participation in our seminars via Zoom before May 30, 2024, please re-register using a new form. - For further information, please click here. |
- Please refrain from making inquiries related to Microeconomic Theory Workshop seminar logistics to CIRJE from now on.
以下本年度終了分
| 日時 | March 5, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Leon Musolff (The Wharton School, The University of Pennsylvania) "Entry Into Two-Sided Markets Shaped By Platform-Guided Search" with Kwok Hao Lee (National University of Singapore Business School) [Paper] |
| Abstract | Consider firms that operate platforms matching buyers and sellers while selling goods themselves. By guiding consumers towards their own products through algorithmic recommendations, these firms could influence market outcomes – a regulatory concern. To investigate, we combine novel data about sales and recommendations on Amazon with a structural model that captures seller entry. Recommendations are highly price-elastic (-20), and many consumers (34%) only consider recommended offers. Hence, algorithmic recommendations raise the demand elasticity (from -8 to -11), intensify price competition, and increase the purchase rate. However, increased competition reduces entry (but the missing merchants are the least efficient). Focusing on self-preferencing: recommendations favor Amazon (equivalent to a 6% price discount), but this skew does not act as a barrier to entry or otherwise harm consumers. Indeed, since consumers prefer Amazon’s offers, “self-preferencing” slightly raises consumer surplus by $9 per product per month (assuming Amazon’s prices remain constant.) |
| Co-Host | The University of Tokyo Market Design Center (UTMD) |
| Organizer | Kei Kawai, Suk Joon Son |
| 日時 | [Irregular Seminar] |
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。詳細は本ウェブサイト上の説明をご確認ください。 ■ 対面会場: 東京大学本郷キャンパス 小島ホール1階第1セミナー室 This seminar is held in-person and online (registration is required for online participation). Please read the instruction above for details. |
| 報告 | Mitsuru Igami (伊神 満) (Yale University, Yale Department of Economics) "Welfare Gains from LCD Innovations, 2001–2011" with Shoki Kusaka, Jeff Qiu, Tuyetanh L. Tran |
| Abstract | We assess the welfare impact of new technologies by using detailed data from theglobal industry of liquid crystal display (LCD) panels. We focus on measuring bothproductivity growth via process innovation and consumer benefits from new products.We find process innovation accounted for most of the welfare gains in the computersegment, whereas product innovation played a major role in the TV segment. Wefurther decompose process innovation into vintage capital and learning by doing, andproduct innovation into larger products and other new varieties. We then conduct aseries of benefit-cost analyses to quantify the social and private returns on technologicalinvestments. Results suggest social returns were large, but most firms’ private returnswere small or negative; competitive pressure forced them to invest nevertheless. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) Empirical Micro Research Seminar |
| Organizer | Kei Kawai, Suk Joon Son, Andrew Griffen |
| 日時 | [Irregular Seminar]
April 2, 2024（火 Tuesday）10:25-12:10 |
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Yuichi Yamamoto (山本裕一) (Hitotsubashi University) "Unawareness and Equilibrium Stability" with Takeshi Murooka |
| Abstract | This paper considers a Bayesian learning problem where strategic players jointly learn an unknown economic state $＼theta$,
and show that one's unawareness about the opponent's overconfidence can have a significant impact on the equilibrium outcome.
We consider a simple environmental problem where players' production, as well as an unknown state $＼theta$, affects the quality of the environment.
Crucially, we assume that one of the players is unrealistically optimistic about the quality of the environment.
When this optimism is common knowledge, the equilibrium outcome is continuous in the amount of optimism, and hence small optimism leads to approximately correct learning of the state $＼theta$.
In contrast, when the optimism is not common knowledge and each player is unaware of the opponent having a different view about the world, the equilibrium outcome is discontinuous, and even vanishingly small optimism leads to completely incorrect learning.
We then analyze a general Bayesian learning model and discuss when such discontinuity arises. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) |
| Organizer | Daisuke Oyama (Shunya Noda)
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| 日時 | April 9, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Mamoru Kaneko (金子守) (University of Tsukuba and Waseda University) "Conceptual Analysis of the Centipede Paradox and its Practical Resolution" by Mamoru Kaneko & Ryuichiro Ishikawa [Slides] |
| Abstract | We start to identify the centipede paradox as the antagonism between the BI (backward induction) outcome in a centipede game and people's responses that Selten indicated for the chain-store paradox. We explore the underlying postulates for the centipede paradox as well as a centipede game. Based on them, we weaken the BI theory so that payoffs are possibly incomparable for a player depending upon his bounded cognitive ability. In this case, he is assumed to follow inertial behavior when decision nodes have some distance from the start. In the CIB (conscious choice/inertial behavior) theory which we develop, when both players have high cognitive abilities, the CIB theory exhibits the same outcome as the BI theory, but when at least one has a low ability, it induces quite opposite outcomes to go to the ending area of the game. We argue that these results are compatible with the postulate for a centipede game leading to cooperation, which is the reason for with people's responses indicated by Selten. These considerations form a resolution of the centipede paradox. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) |
| Organizer | Akihiko Matsui (Shunya Noda)
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| 日時 | April 16, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Kenzo Imamura (今村謙三) (University of Tokyo) "Strategy-proofness and competitive equilibrium with transferable utility: Gross substitutes revisited" Keisuke Bando, Kenzo Imamura, Tomoya Kazumura [Paper] |
| Abstract | We study the strategy-proofness (SP) of the competitive equilibrium selection (CE) mechanism in many-to-one matching with continuous transfers and quasilinear utility. The gross substitutes condition is known to guarantee the existence of CE and SP mechanisms. We show the converse: If a CE and SP mechanism exists, then the valuation of each firm must satisfy the gross substitutes condition. Various conditions for the existence of competitive equilibria have been proposed in the literature. Our results suggest that only the gross substitutes condition guarantees the existence of CE and SP mechanisms. We provide additional implications of our results for investment incentives and policy design. We also examine the two other models—the one with non-quasilinear utility and the one with discrete transfers. In contrast, the gross substitutes condition is not necessary in either model. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) ERATO Kojima Market Design Project |
| Organizer | Shunya Noda
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| 日時 | April 22, 2024 (Monday) 10:25-12:10 |
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。詳細は本ウェブサイト上の説明をご確認ください。 ■対面会場: 東京大学本郷キャンパス 小島ホール1階第1セミナー室 This seminar is held in-person and online (registration is required for online participation). Please read the instruction above for details. |
| 報告 | Kwok Hao Lee (National University of Singapore) "Public Housing at Scale" an old version of the paper: [Paper] |
| Abstract | We consider the design of a large-scale public housing program where consumers face dynamic tradeoffs over apartments rationed via lotteries and prices. We show, theoretically and empirically, that changing rules complements increasing supply. First, we present a motivating example in which supplying more housing leads households to strategically delay their applications. By waiting for “better” developments arriving tomorrow, households forgo mediocre developments available today, resulting in more vacancies. Turning to the data from the mechanism, we formulate a dynamic choice model over housing lotteries and estimate it. Under the existing mechanism, we find that increasing supply fails to lower wait times. However, when a strategyproof mechanism is implemented, vacancies and wait times fall, but prices on the secondary market rise. Under this new mechanism, building more apartments lowers wait times and reduces the upward pricing pressure on the secondary market. |
| Co-Host | Empirical Microeconomics Workshop and UTMD |
| Organizer | Suk Joon Son |
| 日時 | April 23, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Zhaohong Sun (Kyushu University) "Probabilistic Analysis of Stable Matching in Large Markets with Siblings" |
| Abstract | We consider a practical two-sided matching problem that assigns children to daycare centers. Notably, collective preferences expressed by siblings from the same family introduce complementarities that can result in the non-existence of stable matchings, a phenomenon observed in hospital-doctor matching problems involving couples. Intriguingly, stable matchings have been reported in real-world daycare markets, even when a significant number of applicants are children with siblings.
Our research embarks on a systematic exploration to uncover the presence of stable matchings in these real-life markets. We conduct a probabilistic analysis of large random matching markets incorporating sibling preferences. Specifically, we examine scenarios where daycares exhibit similar priorities over children, a common characteristic observed in practical markets. Our analysis highlights that as the market size approaches infinity, the likelihood of stable matchings' existence converges to 1.
To facilitate our investigation, we introduce significant modifications to the Sorted Deferred Acceptance algorithm proposed by \citep{ABH14a}. These adaptations are essential to accommodate a more stringent stability concept, as the original algorithm may yield matchings that fail to adhere to this criterion. Leveraging our revised algorithm, we successfully identify stable matchings across all encountered real-life datasets. Additionally, we conduct comprehensive empirical investigations using synthetic datasets to validate the efficacy of our algorithm in identifying stable matchings. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) ERATO Kojima Market Design Project |
| Organizer | Shunya Noda
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| 日時 | April 30, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Takeshi MUROOKA (室岡健志)(Osaka University) "Procrastination Markets" Paul Heidhues, Botond K˝oszegi, Takeshi Murooka [Paper] |
| Abstract | We develop models of markets with procrastinating consumers where competition operates or is supposed to operate — both through the initial selection of providers and through the possibility of switching providers. As in other work, consumers fail to switch to better options after signing up with a firm, so at that stage they exert little downward pressure on the prices they pay. Unlike in other work, however, consumers are not keen on starting with the best available offer, so price competition fails at this stage as well. In fact, a competition paradox results: an increase in the number of firms or the intensity of marketing increases the frequency with which a consumer receives switching offers, so it facilitates procrastination and thereby potentially raises prices. By implication, continuous changes in marketing costs can, through a self-reinforcing process, lead to discontinuous changes in market outcomes. Sign-up deals do not serve their classically hypothesized role of returning ex-post profits to consumers, and in some cases even exacerbate the failure of price competition. Consumer procrastination thus emerges as a novel source of competition failure that applies in situations where other theories of competition failure do not. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) ERATO Kojima Market Design Project |
| Organizer | Shunya Noda
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| 日時 | May 14, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Donghao Zhu (Institute of Statistical Mathematics) "Pricing Policy and Queue-Length Information Disclosure in On-Demand Service Platforms" |
| Abstract | Online service platforms, such as ride-hailing and freight exchanges, generate net revenues from commissions. Pricing
and queue-length information are strategically used to attract users and maximize profit after considering platform
costs. Dynamic pricing based on queue length can increase net revenue but might decrease user loyalty, incurring
extra costs. Disclosing the queue length impacts customer balking behavior which influences user arrival rates. When
displayed, customers balk at entering if they perceive the queue as too long. If concealed, balking is probabilistic,
driven by the customers’ uncertainty about the waiting time. Using an 𝑀/𝑀/1 queueing model, we examine different
pricing and information disclosure policies to maximize the expected profit of the platform. Optimizing the underlying
semi-Markov decision process requires solving a non-convex quadratically constrained quadratic program. Through
uniformization, we derive optimality equations and compare optimal prices, profits, and throughput. We identify
unique thresholds for pricing and information policies. The preferred pricing policy depends on the extra cost of
implementing dynamic pricing versus a static price. If this cost is low, then dynamic pricing is preferred; otherwise,
a static pricing policy is preferred. The preferred information policy depends on the user’s sensitivity to queue-length
information. Our results reveal that pricing and information policies are complementary. Specifically, both dynamic
pricing and visible information policies increase expected profit, while static pricing and invisible information policies
increase throughput. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) |
| Organizer | Kenzo Imamura
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| 日時 | May 21, 2024（火 Tuesday）10:25-12:10
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | Shota ICHIHASHI (市橋翔太) (Queen's University) "Managing Information Production in Teams" Shota Ichihashi, Fei Li, Dihan Zou [Paper] |
| Abstract | A principal has a stream of related decisions to make under imperfect information. He employs a finite group of agents to acquire information at a cost. The principal designs task allocation and payment schemes to robustly implement all agents engaging in information acquisition and truthful reporting. We characterize the optimal joint design of task allocation and payment scheme, which highlights a trade-off between task assignment diversification and peer monitoring efficiency. The optimal deterministic design features a chain structure of peer monitoring. Stochastic task allocation and payment scheme ease the tension between diversification and monitoring efficiency. |
| Co-Host | The University of Tokyo Market Design Center (UTMD) |
| Organizer | Shunya Noda
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| 日時 | May 30, 2024（木 Thursday）3pm - 4:45pm ※日時に注意
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| 場所 | 本ワークショップは、対面とZoomを利用してのオンラインでの、ハイブリッド開催となります。オンラインでは(事前登録制）となります。詳細は本ウェブサイト下部の説明をご確認ください。 |
| 報告 | In-Koo Cho (Emory University) "Collusive Outcomes Without Collusion" Inkoo Cho, Noah Williams [Paper] |
| Abstract | We develop a model of algorithmic pricing that shuts down every channel for explicit or implicit collusion while still generating collusive outcomes. We analyze the dynamics of a duopoly market where both firms use pricing algorithms consisting of a parameterized family of model specifications. The firms update both the parameters and the weights on models to adapt endogenously to market outcomes. We show that the market experiences recurrent episodes where both firms set prices at collusive levels. We analytically characterize the dynamics of the model, using large deviation theory to explain the recurrent episodes of collusive outcomes. Our results show that collusive outcomes may be a recurrent feature of algorithmic environments with complementarities and endogenous adaptation, providing a challenge for competition policy. |
| Co-Host | |
| Organizer | Akihiko Matsui, (Shunya Noda)
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