Jörn Boehnke

 

About Me

I am a postdoctoral fellow at Harvard University. My research focuses on topics in applied microeconomics, particularly industrial organization and computational economics. I received my PhD in economics from the University of Chicago in 2015.

 

Contact Information

Center of Mathematical Sciences and Applications
Harvard University
20 Garden Street
Cambridge, MA 02138

boehnke@cmsa.fas.harvard.edu
(+1) 312 985 6376

Research

Research Interests

Industrial Organization, Computational Economics, Applied Microeconomics

Research Papers

Evaluating How Much Heterogeneity Can Explain Violations of the “Law of One Price” (with Aaron Bodoh-Creed and Brent R. Hickman)
We use a unique dataset consisting of posted price sales of new Kindle Fire tablets from the eBay “Buy It Now” market platform to assess the degree to which heterogeneity can explain the pricing of seemingly homogeneous products. By combining a rich set of data about each listing with machine learning techniques, we find that we can explain almost 42% of the price variation. An analysis using more traditional data and OLS techniques explains less than 13% of the observed price variation. We conclude that heterogeneity amongst seemingly homogenous products can play a significant role in explaining price variation even in markets for seemingly homogeneous products.

How Efficient are Decentralized Auction Platforms? (with Aaron Bodoh-Creed and Brent R. Hickman)
We provide a model of a decentralized, dynamic auction market platform (e.g., eBay) in which a continuum of buyers and sellers participate in simultaneous, single-unit auctions each period. Our model accounts for the endogenous entry of agents and the impact of intertemporal optimization on bids. We estimate the structural primitives of our model using Kindle sales on eBay. We find that just over one third of Kindle auctions on eBay result in an inefficient allocation with deadweight loss amounting to 14% of total possible market surplus. We also find that partial centralization – for example, running half as many 2-unit, uniform price auctions each day – would eliminate a large fraction of the inefficiency, but yield slightly lower seller revenues. Our results also highlight the importance of understanding platform composition effects – selection of agents into the market – in assessing the implications of market design. We close by proving that the equilibrium of our model with a continuum of buyers and sellers is an approximate equilibrium of the analogous model with a finite number of agents.

The Missing Men: World War I and Female Labor Participation (with Victor Gay)
We explore the effect of military fatalities from World War I on female labor participation in post-war France. We build a unique dataset containing individual level information for all 1.3 million fallen soldiers, and find that the tightness of the marriage market along with negative income shocks generated by the scarcity of men induced many young single women and older widows to enter the labor force permanently after the war, especially in the industrial sector. These findings are robust to alternative empirical strategies, including an instrumental variables strategy based on idiosyncrasies generated by the recruitment process of the army.

Recovery from Bidding Fever: Why pay more than 102% to buy a Gift Card?
On eBay, gift certificates often sell for more than their face values. About 51.6% of Amazon gift certificates sold on eBay, for example, sell for prices that are ‘too high’ – on average 104.1% of face value. People often attribute this apparent overpayment to bidding fever or pseudo-endowment effects. However, using a novel dataset of eBay transactions, I show that about half of all Amazon gift card overpayment occurs in fact in Buy-it-now sales, and thus does not involve bidding, much less bidding fever. My data reveals that overpayment is not random; rather, it is highly cyclic. In fact, overpayments appear to be rationalized by institutional features such as eBay reward programs and special offers. These features affect bidding and buying behavior in meaningful ways and should thus be taken into consideration in future research using eBay data.

Pricing Strategies, Competition, and Consumer Welfare: Evidence from the German and Austrian Retail Gasoline Market
This paper uses spatial and temporal fluctuations in retail gasoline prices to study the effect of competition on pricing behavior and how government-mandated price restrictions impact consumers.
I use hourly price data for more than 16,500 gas stations in Austria and Germany (more than 90% of the market), collected since April 2012. This data is supplemented with manually recorded demand data for selected gas stations as well as traffic data for all German highways, and is wholly unique. I analyze nation-wide price fluctuations, cross-network price patterns, and price competition between adjacent gas stations that directly compete for motorists. Price elasticity estimates for different consumer groups show that the pricing behavior observed in the Austrian and German market cannot be explained as pure demand shocks. The data suggest that gas stations temporally price discriminate: in Germany, gas stations set high prices for price-inelastic business / morning consumers and low prices for the highly elastic leisure / evening consumers. In Austria, governmental regulation prevents gas stations from replicating the patterns in Germany, and might lead to unintended consequences: consumers face a less volatile price with higher daily minima in Austria, forcing price-sensitive consumers to refill at higher average prices.

Design and Implementation of a Privacy Preserving Electronic Health Record Linkage Tool in Chicago (with Abel N. Kho, John P. Cashy, Kathryn L. Jackson, Adam R. Pah, Satyender Goel, John Eric Humphries, Scott D. Kominers, Bala N. Hota, Shannon A. Sims, Brad A. Malin, Dustin D. French, Theresa L. Walunas, David Meltzer, Erin Kaleba, Roderick Jones, William L. Galanter)
Journal of the American Medical Informatics Association, 2015
The Chicago HealthLNK is a shared data resource for researchers and public health officials that deidentifies and links patient data across seven institutions within the city of Chicago. We developed a computer application to perform standardized data cleaning, pre-processing, and hashing of patient identifiers to remove all protected health information using the HIPAA compliant SHA-512 algorithm. Our matching algorithm generated a 92-99% match rate compared with an operational master patient index. Currently the Chicago Health Atlas includes clinical data (diagnoses, medications, laboratory tests, and vital signs) on over 5.6 million records in the Chicago region, and over 1.2 million patients within the city of Chicago (606xx zip codes) for the years 2006 to 2012. A limited set of aggregated clinical data on chronic conditions are made publicly available through a Health Atlas community website.

The Costratified Hilbert Space Structure of an SU(3) Lattice Gauge Model
The weak and strong interactions are modelled by non-abelian gauge field theory. Perturbation methods are the usual approach in dealing with the corresponding gauge fields. For some fundamental phenomena of gauge theory, however, only non-perturbative methods are applicable. In this work, we analyse a toy model of classical SU(3) lattice gauge theory on a single plaquette.
At first, we give an introduction of the mathematical foundations and the model is analysed. In order to reduce the gauge symmetry, we subsequently apply the singular Marsden-Weinstein reduction to the phase space of our system, a Hamiltonian G-manifold. This procedure yields the reduced phase space, a symplectic stratified space.
The reduced phase space is a singular object which is composed of seven different connected components: three zero-dimensional strata, three two-dimensional strata and one four-dimensional stratum. The physical Hilbert space of our system arises by geometric quantisation. We characterise and analyse the Hilbert spaces associated with the singular strata of the SU(3) toy model. The set of these single Hilbert spaces amounts to the structure of a costratified Hilbert space. The results obtained may be regarded as a contribution to non-perturbative quantisation procedures in lattice gauge theory.

Teaching

Lecturer

Economic Research Experience for Undergraduates (BA),  Becker Friedman Institute, University of Chicago,  2017

New Tools for Acquisition / Analysis of Internet Data (PhD),  Harvard,  NBER,  2016

Economic Research Experience for Undergraduates (BA),  Becker Friedman Institute, University of Chicago,  2016

Practical Computing for Economists (PhD),  University of Chicago,  2015

Economic Research Experience for Undergraduates (BA),  Becker Friedman Institute, University of Chicago,  2015

Introduction to Data Acquisition and Data Management for Economic Research (PhD),  UCLA Anderson,  2014

Introduction to Computational Methods in Economics (PhD),  University of Chicago,  2014

Practical Computing for Economists (PhD),  University of Chicago,  2014

Economic Research Experience for Undergraduates (BA),  Becker Friedman Institute, University of Chicago,  2014

Principles of Microeconomics, Economic Analysis 1 (BA),  University of Chicago,  2013

Introduction to Computational Methods in Economics (PhD),  University of Chicago,  2013

Economic Research Experience for Undergraduates (BA),  Becker Friedman Institute, University of Chicago,  2013

Principles of Microeconomics, Economic Analysis 1 (BA),  University of Chicago,  2012

Economic Research Experience for Undergraduates (BA),  Becker Friedman Institute, University of Chicago,  2012

Teaching Assistant

Executive MBA Program, Microeconomics (Gibbs; MBA),  Booth School of Business in Chicago, London, and Hong Kong,  2015

Big Data (Taddy; PhD),  2015

Executive MBA Program, Microeconomics (Gibbs; MBA),  Booth School of Business in Chicago, London, and Hong Kong,  2014

Executive MBA Program, Microeconomics (Stole; MBA),  Booth School of Business in Chicago, London, and Hong Kong,  2014

Evolutionary Game Theory (Szentes; PhD),  University of Chicago,  2014

Introduction to Theory-Based Empirical Methods (Hickman; PhD),  University of Chicago,  2014

Executive MBA Program, Microeconomics (Gibbs; MBA),  Booth School of Business in Chicago, London, and Singapore,  2013

Topics in Matching and Market Design (Kominers; PhD),  University of Chicago,  2013

Evolutionary Game Theory (Szentes; PhD),  University of Chicago,  2013

Introduction to Theory-Based Empirical Methods (Hickman; PhD),  University of Chicago,  2013

Principles of Microeconomics, Economic Analysis 1 - Honors (Lima; BA),  University of Chicago,  2012

Principles of Macroeconomics, Economic Analysis 4 (Santamaria; BA),  University of Chicago,  2011

Quantum Mechanics I and II (Rudolph; DiplPhys),  University of Leipzig,  2007-2008

Calculus I (Freistühler; DiplMath),  University of Leipzig,  2004-2005

Curriculum Vitae

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