Julius Goedde

Julius Goedde

PhD Candidate in Economics, Paris School of Economics

I'm an economist working at the intersection of market design and the digital economy. Combining economic theory, recent econometric & machine learning techniques for causal inference as well as structural econometrics, I study how to design platforms and build trust in markets. I'm very fortunate to be advised by Olivier Tercieux and Liam Wren-Lewis. In spring 2024 I visited Yeon-Koo Che at the Economics department of Columbia University.

I'm on the 2024-25 job market and available for interviews.

Email CV PSE profile

Job Market Paper

Pricing in markets without money: Theory and evidence from home exchanges

Abstract: A growing number of markets use token money instead of real money to allocate resources, such as class seats, food donations or holiday homes. Agents earn token money by supplying and can only spend tokens by consuming within the system. A platform sets goods’ token prices and has to decide whether to clear the market, as in canonical market designs, or to compress prices and ration excess demand. I characterize in a two-type, two-period model under which preference structures compressing prices increases supply and utilitarian welfare. Intuitively, this is possible when income effects are strong, and participation effects are weak. I confirm the models’ predictions on a large home exchange platform, combining proprietary data on the universe of transactions with several natural experiments. I demonstrate large income effects and show that a reform that reduced the price of attractive homes increased their supply and did not reduce their participation. I confirm that many users have a strong preference against for-money platforms, allowing the exchange platform to set non-market-clearing prices. The broader insight is that lessons from traditional markets with transferable utility may not easily extend to markets with token money.

Honoroable mention for "Best Student Paper" of the 18th North American UEA Meeting, selected for "Rising Star" sessions of IIOC 2024 and EARIE 2024

Coverage: blog post by Nick Arnosti

Diagram welfare regimes Compression graph DiD plot Bar graph casual share

Work in Progress

"Misplaced trust? Preferences for similarity in a global online market", with Gabrielle Fack and Liam Wren-Lewis. Draft available soon.

Abstract: This paper analyzes the extent to which individuals prefer to exchange with similar people in a market where trust is important. Using unique data from a digital platform for holiday accommodation, we find that suppliers prefer to trade with guests with similar characteristics. Indeed, when deciding who to trade with, on average they put more weight on similarity than guests’ prior ratings. Analysing measures of suppliers post-exchange satisfaction, however, we find similarity to matter much less than these prior ratings. Suppliers therefore appear to make systematic mistakes by emphasising similarity over measures of past guest behavior. We discuss platform design modifications to enhance overall trust and reduce market segregation.

"A structural model of internal currency systems with endogenous supply", with Sam Altmann and Liam Wren-Lewis.

Abstract: We develop a structural model of an exchange economy where agents trade indivisible goods (homes) with token-money. Building on Menzel (2015), we identify preferences assuming a stable matching in a large market. We estimate the model using transaction and request data from a large platform for exchanging homes. Observing rejected requests allows us to separately identify preferences of both sides. We quantify the welfare and equity effects of different pricing schemes, the initial token endowment of new users and of using a currency system instead of facilitating only two-way exchanges.

"Changing seats: Two-sided markets in the presence of switches", with Xavier Lambin and Jérôme Pouyet.

Abstract: While traditional two-sided market theory assumes that consumers are locked into one side of the market, we argue that in some cases, consumers may switch sides while staying within the same platform. We examine the strategic implications for platforms and their competitors. We test and calibrate the model using proprietary data from a global ride-sharing platform.


Papers Accepted to Peer-Reviewed Conferences

"Pricing in Markets without Money" (short version). Abstract in MATCH-UP 2024


Seminars and Conferences

2024 18th North American Meeting of the Urban Economics Association (UEA), MATCH-UP Oxford, European Association for Research in Industrial Economics (EARIE) conference, ZEW ICT conference, Matching Markets and Inequality Workshop, International Industrial Organization Conference (IIOC), Student Research Breakfast (Columbia), Micro Theory Colloquium (Columbia), Industrial Organization Colloquium (Columbia)
2023 European Winter Meeting of the Econometric Society (EWMES), CIRM Conference 'From matchings to markets. A tale of Mathematics, Economics and Computer Science', Platforms and the Sharing Economy Workshop 2023, Internal Seminar (PSE), Public and Labor Seminar (PSE), Regulation Seminar (PSE)
2022 PSIPSE (PSE)

Grants, Awards and Scholarships

2024 Honoroable mention for "Best Student Paper" of the 18th North American Meeting of the Urban Economics Association (UEA)
2024 Selected for the "Rising Star" session of the European Association for Research in Industrial Economics (EARIE)
2024 ANR-funded research grant "Why (not) to use money in the sharing economy" (4,000 EUR)
2024 Selected for the "Rising Star" session of the International Industrial Organization Conference (IIOC)
2023 Doctoral mobility grant by Paris School of Economics
2023 Doctoral mobility grant by the Columbia Alliance to visit Columbia University
2020 - 2023 3-year PhD funding by l'École Doctorale Économie Panthéon-Sorbonne and Paris School of Economics
2018 - 2020 Scholarship by the German Economy Foundation (sdw)
2018 - 2020 Graduate scholarship by the German Academic Exchange Service (DAAD)