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Email: T.J.Klein at
phone: +31 13 466-8233
fax: +31 13 466-3280










Room K632
Warandelaan 2
5037 AB Tilburg
The Netherlands










Tilburg University
Department of Econometrics and OR
PO Box 90153
5000 LE Tilburg
The Netherlands



Tobias Klein studied economics at the University of Mannheim, the University of California at Berkeley, and University College London. He joined Tilburg University's faculty in 2007 after obtaining a Ph.D. from the University of Mannheim.

He is associate editor of Empirical Economics and the Review of Economics, and editor of a special issue of Information Economics and Policy on current regulatory issues in media and entertainment markets.

His recent research interests include competition in platform markets, sometimes also referred to as two-sided markets. Examples of such markets are media markets and more generally markets in which advertising plays an important role. He studies them using structural empirical models that he also develops further. Besides, he takes an interest in developing tools that are useful for competition policy in media markets and for regulating firms such as Google, Amazon and Apple.

His second line of research concerns the effects of adverse selection and moral hazard and how they can be remedied by innovative designs. In this context, he works on the design of health insurance policies and on the effects of market transparency on adverse selection and moral hazard in online markets.

Tobias Klein's research interests are more broadly related to the idea that recent developments in information and communication technologies together with the availability of big data can help us to address research questions in a novel way if we combine them with tractable models of individual behavior. Insights gained in that way then gives rise to the opportunity to implement welfare-improving policies that are at the same time in the interest of the firms offering a service. This can even lead to the creation of new markets. Examples are the online rating mechanisms used by eBay, Airbnb, Tripadvisor, Yelp, Uber and others that discipline market participants via online ratings and lead to more transparency.

He is co-organizer of the structural econometrics group and teaches econometrics and structural empirical organization at Tilburg University.




Klein, T.J., C. Lambertz and K.O. Stahl (forthcoming): Market Transparency, Adverse Selection, and Moral Hazard,” Journal of Political Economy.

Karlsson, M., T.J. Klein, and N. Ziebarth (forthcoming): “Skewed, Persistent and High before Death: Medical Spending in Germany,” Fiscal Studies.

Affeldt, P., L. Filistrucchi, and T.J. Klein (2013): “Upward Pricing Pressure in Two-Sided Markets,” Economic Journal, 123(572), pp. F505-F523.

Klein, T.J. (2013): “College Education and Wages in the U.K.: Estimating Conditional Average Structural Functions in Nonadditive Models with Binary Endogenous Variables,” Empirical Economics, 44(1), 135-161.

van der Heijden, E., T.J. Klein, W. Müller, and Jan Potters (2012): “Framing Effects and Impatience: Evidence from a Large Scale Experiment,” Journal of Economic Behavior and Organization, 84(2), pp. 701-711.

Bonsang, E. and T.J. Klein (2012): “Retirement and Subjective Well-Being,” Journal of Economic Behavior and Organization, 83(3), pp. 311-329.

Filistrucchi, L., T.J. Klein, and T.O. Michielsen (2012): Assessing Unilateral Merger Effects in a Two-Sided Market: An Application to the Dutch Daily Newspaper Market, Journal of Competition Law and Economics, 8(1), pp. 1-33. A shorter and less technical version with a slightly different focus appeared as: Filistrucchi, L., T.J. Klein, and T.O. Michielsen (2012): Assessing Unilateral Merger Effects in the Daily Newspaper Market, in: J. Harrington and Y. Katsoulakos (eds.): Advances in the Analysis of Competition Policy and Regulation, Edward Elgar Publishing.

Amann, R. and T.J. Klein (2012): Returns to Type or Tenure?, Journal of the Royal Statistical Society, Series A, 175(1), pp. 153-166.

Hullegie, P. and . Klein (2010): The Effect of Private Health Insurance on Medical Care Utilization and Self-Assessed Health in Germany, Health Economics, 19(9), pp. 1048-1062. A shorter version with additional results appeared as: Hullegie, P. and T.J. Klein (2011): “The effect of private health insurance on doctor visits, hospital nights and self-assessed health: Evidence from the German Socio-Economic Panel,” Schmollers Jahrbuch, 131(2), pp. 395-407.

Klein, T.J. (2010): Heterogeneous Treatment Effects: Instrumental Variables without Monotonicity?, Journal of Econometrics, 155(2), pp. 99-116.

Klein, T.J., C. Lambertz, G. Spagnolo, and K.O. Stahl (2009): The Actual Structure of eBays Feedback Mechanism and Early Evidence on the Effect of Recent Changes, International Journal of Electronic Business, 7(3), pp. 301-320.


van Dalen, R. and Klein, T. J. (2014): “Mededingingsbeleid voor internetmarkten met netwerkeffecten," Economisch Statistische Berichten, p. 44-49.

Filistrucchi, L., D. Geradin, E. van Damme, S. Keunen, T.J. Klein, T. Michielsen, and J. Wileur (2010): “Mergers in Two-Sided Markets—A Report to the NMa,” Nederlandse  Mededingingsautoriteit, The Hague, Netherlands.




(See also and my vita for work in progress.)


Skewed, Persistent and High before Death: Medical Spending in Germany
joint with Martin Karlsson and Nicolas Ziebarth

We use claims panel data from a big German private health insurer to provide detailed individual-level evidence on medical spending between 2005 and 2011. This includes evi- dence on the distribution of medical spending, the dependence of medical spending on age and other demographic characteristics, its persistence, and how medical spending evolves in the years before death. Our main findings are that health care spending more than dou- bles between ages 50 and 80 and that spending is very concentrated: the top 10% of all spenders are responsible for 53% of all medical spending in a given year. There is a fifty percent probability that individual expenditures lie in the same quintile of the distribution after five years, both for very high and very low cost individuals. Medical spending in the year before death is six times higher for the deceased, as compared to spending of every- body else, and accounts for 5.6% of lifetime spending. Females use more outpatient care and have higher spending in younger ages, whereas males have higher spending in older ages, particularly for inpatient care, and die younger. The presentation of these empirical facts is framed by an institutional discussion of the German health care system, a compari- son between publicly and privately insured, and a discussion of medical spending trends in aggregate-level data.


The effects of access to health insurance for informally employed individuals in Peru
joint with Noelia Bernal and Miguel A. Carpio

In many countries large parts of the population do not have access to health insurance. Peru has made an effort to change this in the early 2000’s. The institutional setup gives rise to the rare opportunity to study the effects of health insurance coverage exploiting a sharp regression discontinuity design. We find large effects on utilization that are most pronounced for the provision of curative care. Individuals seeing a doctor leads to increased awareness about health problems and generates a potentially desirable form of supplier- induced demand: they decide to pay themselves for services that are not part of the benefit package.


Price Competition in Two-Sided Markets with Heterogeneous Consumers and Network Effects

joint with Lapo Filistrucchi
NET Institute Working Paper #13-20 

We model a two-sided market with heterogeneous customers and two heterogeneous network effects. In our model, customers on each market side care differently about both the number and the type of customers on the other side. Examples of two-sided markets are online platforms or daily newspapers. In the latter case, for instance, readership demand depends on the amount and the type of advertisements. Also, advertising demand depends on the number of readers and the distribution of readers across demographic groups. There are feedback loops because advertising demand depends on the numbers of readers, which again depends on the amount of advertising, and so on. Due to the difficulty in dealing with such feedback loops when publishers set prices on both sides of the market, most of the literature has avoided models with Bertrand competition on both sides or has resorted to simplifying assumptions such as linear demands or the presence of only one network effect. We address this issue by first presenting intuitive sufficient conditions for demand on each side to be unique given prices on both sides. We then derive sufficient conditions for the existence and uniqueness of an equilibrium in prices. For merger analysis, or any other policy simulation in the context of competition policy, it is important that equilibria exist and are unique. Otherwise, one cannot predict prices or welfare effects after a merger or a policy change. The conditions are related to the own- and cross-price effects, as well as the strength of the own and cross network effects. We show that most functional forms used in empirical work, such as logit type demand functions, tend to satisfy these conditions for realistic values of the respective parameters. Finally, using data on the Dutch daily newspaper industry, we estimate a flexible model of demand which satisfies the above conditions and evaluate the effects of a hypothetical merger and study the effects of a shrinking market for offline newspapers.


Ownership and Control in a Competitive Industry
joint with Heiko Karle and Konrad O. Stahl
TILEC Discussion Paper No. 2011-013

We study a differentiated product market in which an investor initially owns a controlling stake in one of two competing firms and may acquire a non-controlling or a controlling stake in a competitor, either directly using her own assets, or indirectly via the controlled firm. While industry profits are maximized within a symmetric two product monopoly, the investor attains this only in exceptional cases. Instead, she sometimes acquires a non-controlling stake. Or she invests asymmetrically rather than pursuing a full takeover if she acquires a controlling one. Generally, she invests indirectly if she only wants to affect the product market outcome, and directly if acquiring shares is profitable per se.




Dynamic Discrete Choice Models: Methods, Matlab Code, and ExercisesJaap H. Abbring and Tobias J. Klein

This document supports the first Matlab computing sessions in our PhD elective course Empirical Industrial Organization II in CentER Tilburg's Research Master in Economics program (230323) and in the Finnish Doctoral Programme in Economics (SEIO11). It contains some notes on the theory of dynamic discrete choice models and on methods for their computation and estimation. It is centered around some basic Matlab code for solving, simulating, and empirically analyzing a simple dynamic discrete choice model. Student exercises ask students to extend this code to apply different and more advanced computational and econometric methods to a wider range of models.


Merger Simulation in a Two-Sided Market: A simple logit example
Tobias J. Klein

We present a simple example of a two-sided market in Matlab. There are logit models on either side of the market. We generate data from that model and then proceed as if one could in a structural empirical study. In particular, we recover marginal cost, conduct a SSNIP test, calculate UPP, and finally conduct a merger simulation. The zip file contains a document with a detailed explanation of the setup, slides that have been used for teaching, as well as Matlab code.




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