christoph.carnehl@unibocconi.it

Curriculum Vitae

Welcome! I am an Assistant Professor in the Department of Economics at Bocconi University. Prior to joining Bocconi, I obtained my PhD at the University of Mannheim.

My research interests lie primarily in the field of Microeconomic Theory. In particular, I am interested in dynamic problems with evolving information. The main applications of my theoretical research lie in the economics of science, the economics of innovation, and industrial organization more broadly.

I am also interested in empirical work; so far, I have been working on the interaction of pricing strategies with online ratings, the estimation of auction models, and the analysis of merger policy.


On Risk an Time Pressure: When to Think and When to Do

(with Johannes Schneider, Journal of the European Economic Association, 2023)

Abstract

We study the tradeoff between fundamental risk and time. A time-constrained agent has to solve a problem. She dynamically allocates effort between implementing a risky initial idea and exploring alternatives. Discovering an alternative implies progress that has to be converted to a solution. As time runs out, the chances of converting it in time shrink. We show that the agent may return to the initial idea after having left it in the past to explore alternatives. Our model helps explain so-called false starts. To finish fast, the agent delays exploring alternatives reducing the overall success probability.


[working paper], [slides]


Pricing for the Stars: Dynamic Pricing in the Presence of Rating Systems

(with André Stenzel and Peter Schmidt, Management Science, 2024)

Abstract

Maintaining good ratings increases the profits of sellers on online platforms. We analyze the role of strategic pricing for ratings management in a setting where a monopolist sells a good of unknown quality. Higher prices reduce the value for money, which on average worsens reviews. However, higher prices also induce only those consumers with a strong taste for the product to purchase, which on average improves reviews. Our model flexibly parametrizes the two effects. This parametrization can rationalize the observed heterogeneity in the relationship between reviews and prices. Based on an analytic characterization of the optimal dynamic pricing strategy, we study a platform's choice of the sensitivity of its rating system to incoming reviews. The optimal sensitivity depends on the effect of prices on reviews and on how the platform weighs consumers and sellers in its objective. While sellers always benefit from more sensitivity, consumers may suffer from higher prices and from slower learning from reviews due to endogenously emerging price and rating cycles.


[working paper], [EC 20], [Mathematica]


Epidemics with Behavior

(with Satoshi Fukuda and Nenad Kos, Journal of Economic Theory, 2023)

Abstract

We study social distancing in an epidemiological model. Distancing reduces the individual's probability of getting infected but comes at a cost. Equilibrium distancing flattens the curve and decreases the final size of the epidemic. We examine the effects of distancing on the outset, the peak, and the final size of the epidemic. First, the prevalence increases beyond the initial value only if the transmission rate is in the intermediate region. Second, the peak of the epidemic is non-monotonic in the transmission rate. A reduction in the transmission rate can increase the peak. However, a decrease in the cost of distancing always flattens the curve. Third, both a reduction in the transmission rate as well as a reduction in the cost of distancing decrease the final size of the epidemic. Our results suggest that public policies that decrease the transmission rate can lead to unintended negative consequences in the short run but not in the long run. Therefore, it is important to distinguish between interventions that affect the transmission rate and interventions that affect contact rates.


[working paper]


Asymmetries in Procurement Auctions: Efficiency vs. Information

(with Stefan Weiergraeber, International Journal of Industrial Organization, 2023)

Abstract

We develop a structural empirical model of procurement auctions with private and common value components and bidder asymmetries in both dimensions. While each asymmetry can explain the dominance of a firm, they have opposite welfare implications. We propose a novel empirical strategy to quantify the two asymmetries using detailed contract-level data on the German market for railway passenger services. Our results indicate that the incumbent is slightly more cost-efficient and has substantially more information about future ticket revenues than its competitors. If bidders’ common value asymmetry was eliminated, the median probability of selecting the efficient firm would increase by 61%-points.


[working paper]

A Quest for Knowledge

(with Johannes Schneider, revise and resubmit at Econometrica)

Abstract

Is more novel research always desirable? We develop a model in which knowledge shapes society's policies and guides the search for discoveries. Researchers select a question and how intensely to study it. The novelty of a question determines both the value and difficulty of discovering its answer. We show that the benefits of discoveries are nonmonotone in novelty. Knowledge expands endogenously step-by-step over time. Through a dynamic externality, moonshots - research on questions more novel than what is myopically optimal - can improve the evolution of knowledge. Moonshots induce research cycles in which subsequent researchers connect the moonshot to previous knowledge.


[pdf], [slides], [video], [Twitter], [Matlab]


Informative Milestones in Experimentation

Abstract

I study a continuous-time moral hazard problem with learning about a two-stage project of unknown quality. The first-stage arrival time is informative but not conclusive about the project’s quality. Due to the informativeness, the optimal contract features a combination of continuation value and intermediate bonus payments as a reward. There is a negative correlation between the first success time and the share of bonus payments in the reward. Second-stage deadlines adjust to the first-stage success time: early successes are rewarded with longer deadlines in the second stage. When agent replacement between stages is possible, the principal will replace the agent if the first success arrives late.


[pdf]


Value for Money and Selection: How Pricing Affects Airbnb Ratings

(with Kevin Tran, Maximilian Schaefer and André Stenzel)

Abstract

We study Airbnb hosts' strategic pricing incentives when prices affect ratings. Two channels determine the price-rating interaction: higher prices reduce the value for money, worsening ratings, but increase the taste-based valuation of travelers, improving ratings. The price further determines the frequency of rating updates through its effect on demand. Our empirical results show a dominant value-for-money effect and that hosts lower their prices to surpass rating thresholds. We provide evidence that hosts benefit from low entry prices: offering a median entry discount of seven percent improves medium-run monthly revenues by three percent.


[pdf]


Time-Varying Cost of Distancing: Distancing Fatigue and Lockdowns

(with Satoshi Fukuda and Nenad Kos)

Abstract

We study a behavioral SIR model with time-varying costs of distancing. The two main causes of the variation in the cost of distancing we explore are distancing fatigue and public policies. We show that for a second wave of an epidemic to arise, a steep increase in distancing cost is necessary. Distancing fatigue cannot increase the distancing cost sufficiently fast to create a second wave. However, public policies that discontinuously affect the distancing cost can create a second wave. With that in mind, we characterize the largest change in the distancing cost (due to, for example, lifting a public policy) that will not cause a second wave. Finally, we provide a numerical analysis of public policies under distancing fatigue and show that a strict lockdown at the beginning of an epidemic (as, for example, recently in China) can lead to unintended adverse consequences. Once the policy is lifted, the disease spreads rapidly due due to the accumulated distancing fatigue of the individuals causing high prevalence levels.


[pdf]


Strategic Pricing and Ratings

(with Anton Sobolev, Konrad Stahl and André Stenzel)

Abstract

A seller serving two generations of short lived heterogeneous consumers sells a product under uncertain demand. We characterize the seller's optimal pricing, taking into account that the current period's price affects the information transmission to the next period consumers via consumer ratings. While the seller always prefers to generate more information, it is not necessarily in the consumers' interest. We characterize situations in which consumer surplus and welfare are decreasing in additional information. We provide conditions under which aggregate consumer surplus and welfare are lower with than without a rating system.


[pdf]



Competitive Procurement Design: Evidence from German Railway Passenger Services

(with Matthias Hunold)

Abstract

We study competitive awarding procedures of short haul railway passenger services in Germany from 1995 to 2011 by means of a newly collected data set. In particular, we use regression techniques to investigate the determinants of the number of bidders, the identity of the winning bidder and the subsidy level. We find that there are more bidders when the contract duration is high and the revenue risk low. The dominant operator is more likely to win contracts if it is the incumbent, the network is large, the contract duration is high, when used rolling stock is admitted and when there are few other bidders.


[pdf]


Christoph Carnehl

Bocconi University
Department of Economics
Via Roentgen 1
20136 Milan, Italy
+39 02 5836 5277
christoph.carnehl@unibocconi.it