Prof. Dr. Frank Mueller-Langer

Articles in Refereed Journals

McCabe, Mark J.; Mueller-Langer, Frank (2024). Open Access Is Shaping Scientific Communication Funders and Publishers Should Roll Out Policies in Ways to Support Their Evaluation, Science, 385 (6714), 1170-1172. DOI

Gomez-Herrera, Estrella; Mueller-Langer, Frank (2024). Does Information Disclosure Affect the Gender Gap in Bidding Behavior? Empirical Evidence from a Natural Experiment on a Large Online Labor Platform, Labour Economics, 90. DOI

• Exploiting an exogenous change in information disclosure on one of the largest online labor platforms worldwide, we assess how the provision of more information on the employers’ willingness to pay (WTP) and the required experience level of workers affects the gender gap in bidding behavior. We find that female workers make lower wage proposals than male workers if the employers’ WTP for a project, as given by its budget, is disclosed in addition to the (exogenously enforced) experience level of workers that employers deem necessary for the job, i.e., low, intermediate, or high. In addition, we do not find robust empirical support for the hypothesis that female workers’ under-confidence in their skills increases the gender gap in bidding behavior. Finally, we find a statistically significant gender wage gap of 16.8 %, which is reduced to 1.5 % when we control for employer, worker, and project characteristics. Once we include workers’ wage proposals in our agreed-upon wage regressions, the gender wage gap virtually disappears (0.2 %) and is statistically insignificant. This suggests that gender differences in wage expectations pertain to gender differences in wages.

Jorzik, Nathalie; Kirchhof, Paula Johanna; Mueller-Langer, Frank (2023). Industrial Data Sharing and Data Readiness: A Law and Economics Perspective, European Journal of Law and Economics 2023. DOI

• We study the incentives and welfare properties of industrial data sharing taking into account the data (economy) readiness of companies. We differentiate between two regulatory settings. First, there is no compulsion for companies to provide data. Companies, which also use the data for other corporate purposes, decide whether to share their data voluntarily. Second, there is a regulatory requirement on the minimum amount of data to be shared by the data provider. We assume that data sharing affects the data provider’s value of the data. The magnitude and sign of this effect have an impact on the optimal investment level of data generation and overall welfare in the different cases under study. Our results suggest that the implementation of a data-sharing policy has ambiguous welfare properties. It has positive welfare properties if (a) the data receiving firm does not pay too much for the data, (b) the data receiving firm benefits enough from the data provider’s data generating effort, and (c) the intensified competition due to data sharing is not too harmful to the data provider. In contrast, it will always have negative welfare properties if the data provider’s minimum amount of data to be shared under the policy is prohibitively high such that no data is created in the first place. Our results also suggest that a positive effect of data sharing on the data-generating company’s value of the data and its data economy readiness positively affect the incentives to share data. Finally, we find that data sharing under a data-sharing policy leads to a lower data quality if the data economy readiness of the data-generating company is too low.
• Also published as: Max Planck Institute for Innovation & Competition Research Paper No. 23-22

Mueller-Langer, Frank; Gomez-Herrera, Estrella (2022). Mobility Restrictions and the Substitution between On-site and Remote Work: Empirical Evidence from a European Online Labour Market, Information Economics and Policy 2022. DOI

• Intensified by the COVID-19 pandemic, online labour markets are at the core of the economic and policy debate about the future of work and the conditions under which we work online. We analyse the effects of an increase in the cost of on-site work induced by COVID-19-related mobility restrictions on the substitution between on-site and remote job postings and between on-site and remote hires. We benefit from the fact that the implementation of stay-at-home requirements varies by country, time and level. We use unique company data from a large European online labour market. We provide empirical evidence for a positive effect of stay-at-home restrictions on job postings and hires of remote work relative to on-site work. Overall, our results suggest that employers are substituting remote employment for on-site employment, while there is no substantial change in overall employment.
• Also published as: Max Planck Institute for Innovation & Competition Research Paper No. 21-26

Duch-Brown, Nestor; Gomez-Herrera, Estrella; Mueller-Langer, Frank; Tolan, Songül (2022). Market Power and Artificial Intelligence Work on Online Labour Markets, Research Policy, 51 (3). DOI

• We investigate three alternative but complementary indicators of market power on one of the largest online labour markets (OLMs) in Europe: (1) the elasticity of labour demand, (2) the elasticity of labour supply, and (3) the concentration of market shares. We explore how these indicators relate
  to an exogenous change in platform policy. In the middle of the observation period, the platform made it mandatory for employers to signal the rates they were willing to pay as given by the level of experience required to perform a project, i.e., entry, intermediate or expert level. We find a positive labour supply elasticity ranging between 0.06 and 0.15, which is higher for expert-level projects. We also find that the labour demand elasticity increased while the labour supply elasticity decreased after the policy change. Based on this, we argue that market-designing platform providers can influence the labour demand and supply elasticities on OLMs with the terms and conditions they set for the platform. We also explore the demand for and supply of AI-related labour on the OLM under study. We provide evidence for a significantly higher demand for AI-related labour (ranging from +1.4% to +4.1%) and a significantly lower supply of AI-related labour (ranging from -6.8% to -1.6%) than for other types of labour. We also find that workers on AI projects receive 3.0%-3.2% higher wages than workers on non-AI projects.
• Also published as: Max Planck Institute for Innovation & Competition Research Paper No. 22-01

Mueller-Langer, Frank; Watt, Richard (2021). Optimal Pricing and Quality of Academic Journals and the Ambiguous Welfare Effects of Forced Open Access: A Two-Sided Model, Managerial and Decision Economics 2021. DOI

• We analyze optimal pricing and quality of a monopolistic journal and the optimality of open access in a two-sided model. The predominant aspect of the model that determines the quality levels at which open access is optimal is the nature of the relationship between readers and authors in a journal. In contrast to the previous literature, we firstly show that there exist scenarios in which open access is a feature of high-quality journals. Second, we find that the removal of copyright (and thus forced open access) will likely increase both readership and authorship, will decrease journal profits, and may increase social welfare.
• Also published as: RatSWD Working Paper Series No. 223
• Also published as: TILEC Discussion Paper No. 2012-019

Jorzik, Nathalie; Mueller-Langer, Frank (2020). Multilateral Stability and Efficiency of Trade Agreements: A Network Formation Approach, The World Economy, 43 (2), 355-370. DOI

• We study the endogenous network formation of bilateral and multilateral trade agreements by means of hypergraphs and introduce the equilibrium concept of multilateral stability. We consider multicountry settings with a firm in each country that produces a homogeneous good and competes as a Cournot oligopolist in each market. Under endogenous tariffs, we find that a multilateral trade agreement governing the rules and norms of tariff setting, that is the WTO/GATT regime itself, together with a bilateral preferential trade agreement (PTA) is multilaterally stable. We also find that the existence of the WTO is necessary for the stability of the trading system. We further analyse the impact of PTAs on multilateral tariffs within the WTO. We find that the formation of PTAs increases countries' incentives for multilateral tariff reduction.

Mueller-Langer, Frank; Scheufen, Marc; Waelbroeck, Patrick (2020). Does Online Access Promote Research in Developing Countries? Empirical Evidence from Article-Level Data, Research Policy, 49 (2). DOI

• Universities in developing countries have rarely been able to subscribe to academic journals in the past. The “Online Access to Research in the Environment” initiative (OARE) provides institutions in developing countries with free online access to more than 11,500 environmental science journals. We analyze the effect of OARE on (1) scientific output and (2) scientific input as a measure of accessibility in five developing countries. We apply difference-in-difference-in-differences estimation using a balanced panel with 249,000 observations derived from 36,202 journal articles published by authors affiliated with 2,490 research institutions. Our approach allows us to explore effects across scientific fields, i.e. OARE vs. non-OARE fields, within institutions and before and after OARE registration. Variation in online access to scientific literature is exogenous at the level of scientific fields. We provide evidence for a positive marginal effect of online access via OARE on publication output by 29.6% with confidence interval (18.5%, 40.6%) using the most conservative specification. This adds up to 2.07 additional articles due to the OARE program for an average institution publishing 7.0 articles over the observation period. Moreover, we find that OARE membership eases the access to scientific content for researchers in developing countries, leading to an increase in the number of references by 8.4% with confidence interval (5.6%, 11.2%) and the number of OARE references by 14.5% with confidence interval (7.5%, 21.5%). Our results suggest that productive institutions benefit more from OARE and that the least productive institutions barely benefit from registration.

Martens, Bertin; Mueller-Langer, Frank (2020). Access to Digital Car Data and Competition in Aftersales Services, Journal of Competition Law and Economics, 16 (1), 116-141. DOI

• This study looks at car data markets from an economic perspective. We start from several options for the technical characteristics of data access points that have been discussed among stakeholders in the automotive industry. We examine the structure of data markets that are likely to emerge from these characteristics and the implications for the welfare of manufacturers, aftermarket service providers and drivers. Car manufacturers face competition in car markets and aftersales services. However, they can design the car data architecture to ensure their exclusive access to the data. That would give them a monopoly in the market for car data from their brand. They can use this to increase their leverage on aftersales services markets. Our baseline scenario is the Extended Vehicle proposal that manufacturers prefer. This ensures their data access monopoly and enables them to maximize revenue from data and data-driven aftersales services. It reduces welfare for drivers and aftersales service providers. Two technical variations on the baseline scenario reduce manufacturers' leverage over data server governance and their monopolistic power. That could reduce social welfare losses and transfer more surplus to drivers and service providers, compared to the baseline scenario. Other scenarios examine alternative data access gateways, for instance by keeping the OBD plug open and by applying real time data portability under the GDPR. These scenarios may offer some scope for regulators if they wish to keep alternative data access channels open in order to stimulate competition in aftersales services markets. However, they entail additional hardware and switching costs for consumers, compared to the baseline and are therefore partial and imperfect substitutes. In two final scenarios we examine the market position of B2B data marketplaces and consumer media services platforms. The potential for data aggregation across car brands and other sources creates some possibilities for these platforms to provide a counterweight to monopolistic behaviour by the manufacturers. However, manufacturers' control over the data supply and access to the in-car human interface ensures that they retain substantial leverage over these platforms. Regulators may consider creating the conditions for a more level playing field between OEM services and third-party aftersales service providers.
• Also published at SSRN

Mueller-Langer, Frank; Fecher, Benedikt; Harhoff, Dietmar; Wagner, Gert G. (2019). Replication Studies in Economics — How Many and Which Papers Are Chosen for Replication, and Why?, Research Policy, 48 (1), 62-83. DOI

• We investigate how often replication studies are published in empirical economics and what types of
  journal articles are replicated. We find that between 1974 and 2014 0.1% of publications in the top 50
  economics journals were replication studies. We consider the results of published formal replication
  studies (whether they are negating or reinforcing) and their extent: Narrow replication studies are
  typically devoted to mere replication of prior work, while scientific replication studies provide a
  broader analysis. We find evidence that higher-impact articles and articles by authors from leading
  institutions are more likely to be replicated, whereas the replication probability is lower for articles that
  appeared in top 5 economics journals. Our analysis also suggests that mandatory data disclosure
  policies may have a positive effect on the incidence of replication.
• Also published as JRC Digital Economy Working Paper 2018-01

Watt, Richard; Mueller-Langer, Frank (2018). Indirect Copyright Infringement Liability for an ISP: An Application of the Theory of the Economics of Contracts under Asymmetric Information, Review of Economic Research on Copyright Issues, 15 (2), 57-79.

• http://www.serci.org/rerci_files/2018/wattandmueller.pdf

Mueller-Langer, Frank; Watt, Richard (2018). How Many More Cites is a $3,000 Open Access Fee Buying You? Empirical Evidence from a Natural Experiment, Economic Inquiry, 56 (2), 931-954. DOI

• (Gewinner des “Sloan Economics of Knowledge Contribution and Distribution”- Forschungswettbewerbs 2013)
• We analyze the effect of open access (OA) status of journal articles on citations. Using cross-sectional and panel data from mathematics and economics, we perform negative binomial, Poisson, and generalized method of moments/instrumental variable methods regressions. We benefit from a natural experiment via hybrid OA pilot agreements. Citations to pre-prints allow us to identify the intrinsic quality of articles prior to journal publication. Overall, our analysis suggests that there is no hybrid OA citation benefit. However, for the subpopulation of articles without OA pre- or post-prints, we find positive hybrid OA effects for the full sample and each discipline separately.
• Also published in SSRN under the title: The Hybrid Open Access Citation Advantage: How Many More Cites is a $3,000 Fee Buying You?

Mueller-Langer, Frank; Andreoli-Versbach, Patrick (2018). Open Access to Research Data: Strategic Delay and the Ambiguous Welfare Effects of Mandatory Data Disclosure, Information Economics and Policy, 42, 20-34. DOI

• Mandatory data disclosure is an essential feature for credible empirical work but comes at a cost: First, authors might invest less in data generation if they are not the full residual claimants of their data after their first publication. Second, authors might "strategically delay" the time of submission of papers in order to fully exploit their data in subsequent research. We analyze a three-stage model of publication and data disclosure. We derive exact conditions for positive welfare effects of mandatory data disclosure. However, we find that the transition to mandatory data disclosure has negative welfare properties if authors delay strategically.
• Also published as: Max Planck Institute for Innovation and Competition Research Paper No. 14-09

Mueller-Langer, Frank; Andreoli-Versbach, Patrick (2017). Leading-Effect, Risk-Taking and Sabotage in Two-Stage Tournaments: Evidence from a Natural Experiment, Journal of Economics and Statistics/Jahrbücher für Nationalökonomie und Statistik, 237 (1), 1-28. DOI

• Existing theory suggests that three “order effects” may emerge in multi-stage tournaments with information feedback. First, participants adjust effort across stages, which could advantage the leading participant who faces a larger “effective prize” after an initial victory (leading-effect). Second, leading participants might engage in sabotage activities to protect their lead thereby decreasing the rivals’ output. Finally, participants lagging behind may increase risk at the final stage as they have “nothing to lose” (risk-taking). The expected order effects based on existing theory cannot be supported empirically in a natural experiment setting, where professional teams compete in a two-stage tournament with asymmetric initial conditions and clear incentives.
• Replication data to the article

Mueller-Langer, Frank; Andreoli-Versbach, Patrick (2017). Replication data for "Leading-Effect, Risk-Taking and Sabotage in Two-Stage Tournaments". Version: 1, Journal of Economics and Statistics. Dataset 2017. DOI

• Journal article "Leading-Effect, Risk-Taking and Sabotage in Two-Stage Tournaments"

Andreoli-Versbach, Patrick; Mueller-Langer, Frank (2014). Open Access to Data: An Ideal Professed but Not Practised, Research Policy, 43 (9), 1621-1633. DOI

• Data-sharing is an essential tool for replication, validation and extension of empirical results. Usinga hand-collected data set describing the data-sharing behaviour of 488 randomly selected empiricalresearchers, we provide evidence that most researchers in economics and management do not sharetheir data voluntarily. We derive testable hypotheses based on the theoretical literature on information-sharing and relate data-sharing to observable characteristics of researchers. We find empirical supportfor the hypotheses that voluntary data-sharing significantly increases with (a) academic tenure, (b) thequality of researchers, (c) the share of published articles subject to a mandatory data-disclosure policyof journals, and (d) personal attitudes towards “open science” principles. On the basis of our empiricalevidence, we discuss a set of policy recommendations.

Mueller-Langer, Frank (2013). Neglected Infectious Diseases: Are Push and Pull Incentive Mechanisms Suitable for Promoting Drug Development Research?, Health Economics, Policy and Law, 8 (2), 185-208. DOI

• Tag Cambridge DOI
• Infectious diseases are among the main causes of death and disability
  in developing countries, and they are a major reason for the health disparity
  between rich and poor countries. One of the reasons for this public health
  tragedy is a lack of lifesaving essential medicines, which either do not exist or
  badly need improvements. In this article, we analyse which of the push and pull
  mechanisms proposed in the recent literature may serve to promote research into
  neglected infectious diseases. A combination of push programmes that subsidise
  research inputs through direct funding and pull programmes that reward
  research output rather than research input may be the appropriate strategy to
  stimulate research into neglected diseases. On the one hand, early-stage (basic)
  research should be supported through push mechanisms, such as research grants
  or publicly financed research institutions. On the other hand, pull mechanisms,
  such as prize funds that link reward payments to the health impacts of effective
  medicines, have the potential to stimulate research into neglected diseases.

Mueller-Langer, Frank (2012). Parallel Trade and Its Ambiguous Effects on Global Welfare, Review of International Economics, 20 (1), 177-185.

Mueller-Langer, Frank; Scheufen, Marc (2011). The Google Book Search Settlement: A Law and Economics Analysis, Review of Economic Research on Copyright Issues, 8 (1), 7-50.

• Auch erschienen als: Max Planck Institute for Intellectual Property & Competition Law Research Paper No. 11-06
• Beginning in December 2004 Google has pursued a new project to create a book search engine (Google Book Search). The project has released a storm of controversy around the globe. While the supporters of Google Book Search conceive the project as a first reasonable step towards unlimited access to knowledge in the information age, its opponents fear profound negative effects due to an erosion of copyright law. Our law and economics analysis of the Book Search Project suggests that – from a copyright perspective – the proposed settlement may be beneficial to right holders, consumers, and Google. For instance, it may provide a solution to the still unsolved dilemma of orphan works. From a competition policy perspective, we stress the important aspect that Google’s pricing algorithm for orphan and unclaimed works effectively replicates a competitive Nash-Bertrand market outcome under post-settlement, third-party oversight.
• Available at SSRN

Mueller-Langer, Frank; Watt, Richard (2010). Copyright and Open Access for Academic Works, Review of Economic Research on Copyright Issues, 7 (1), 45-65.

• Auch erschienen als: Max Planck Institute for Intellectual Property, Competition & Tax Law Research Paper No. 10-09
• In a recent paper, Prof. Steven Shavell (see Shavell, 2009) has argued strongly in favor of eliminating copyright from academic works. Based upon solid economic arguments, Shavell analyses the pros and cons of removal of copyright and in its place to have a pure open access system, in which authors (or more likely their employers) would provide the funds that keep journals in business. In this paper we explore some of the arguments in Shavell’s paper, above all the way in which the distribution of the sources of journal revenue would be altered, and the feasible effects upon the quality of journal content. We propose a slight modification to a pure open access system which may provide for the best of both the copyright and open access worlds.
• Available at SSRN

Mueller-Langer, Frank (2009). Does Parallel Trade Freedom Harm Consumers in Small Markets?, Croatian Economic Survey, 11 (1), 11-41.

Contributions to Collected Editions

Mueller-Langer, Frank (2014). Copyright and Parallel Trade, in: Richard Watt (ed.), Handbook Economics of Copyright - A Guide for Students and Teachers, 287-310. Cheltenham, UK; Northampton, MA: Edward Elgar.

Mueller-Langer, Frank; Scheufen, Marc (2013). Academic Publishing and Open Access, in: Christian Handke, Ruth Towse (eds.), Handbook of Digital Creative Economy, 365-377. Cheltenham, UK; Northampton, MA: Edward Elgar.

• Also published as: Max Planck Institute for Intellectual Property & Competition Law Research Paper No. 13-03
• With the spread of the internet and new opportunities for publishing academic works digitally at virtually no costs, the traditional copyright model has recently been put under critical review which is for at least two reasons: First and foremost, a vast increase in subscription prices for academic journals has forced (university) libraries to significantly cut their journal portfolios. Second, copyright seems negligible in academia as researchers are motivated by reputation gains and CV effects rather than direct financial returns from publishing their works. As a consequence, the promotion of Open Access (OA) to scientific research is claimed as the perceived future of academic publishing in the information age. This paper critically reviews the OA debate by discussing theoretical and empirical arguments on the role of copyright in publishing scientific outcomes. A brief historical perspective introduces to the changed environmental conditions for scholarly publishing, pointing to a new trade-off in the digital age. By framing the debate in a broader literature stream and related issues, we provide with caveat for further research and a glimpse of possible future scenarios. It is shown that copyright may be both a blessing and a curse in establishing an effective framework for scientific progress.
• Available at SSRN

Mueller-Langer, Frank; Schäfer, Hans-Bernd (2009). Strict liability versus negligence, in: Michael Faure (ed.), Tort Law and Economics, Chapter 1 (Encyclopedia of Law and Economics), 3-45. Edward Elgar: Cheltenham; Northampton, Mass. 2009.

• The purpose of this chapter is to compare negligence rules and strict liability rules and to examine the allocative effects resulting from the application of different liability regimes. It first discusses unilateral accidents, while the more complicated bilateral cases follow afterwards. Each section starts with a discussion of the rule of no liability before moving on to various forms of negligence and ending with various strict liability rules. At the end of each section, there is a discussion on how results change when relaxing specific assumptions. The various aspects are summarised focusing on the question of whether the outcome under a specific liability regime is efficient or not. We also discuss several more specific topics of interest, for example, the information generating consequence of negligence, the allocative effects of various liability rules when agents enter into a contractual relationship, product liability, cases of ‘joint liability’, the impact of uncertain legal standards, and the interaction between liability law and insurance.
• Available at SSRN

Further Publications, Press Articles, Interviews

Gomez-Herrera, Estrella; Mueller-Langer, Frank (2020). Gibt es geschlechtsspezifische Lohnunterschiede auf Online-Arbeitsmärkten?, Ökonomenstimme 2020.

• https://www.oekonomenstimme.org/artikel/2020/04/gibt-es-geschlechtsspezifische-lohnunterschiede-auf-online-arbeitsmaerkten/

Mueller-Langer, Frank; Scheufen, Marc (2011). Die ökonomische Analyse geistiger Eigentumsrechte (Economic Analysis of Intellectual Property Rights), Wirtschaftswissenschaftliches Studium: Zeitschrift für Ausbildung und Hochschulkontakt, 40 (3), 137-142.

Mueller-Langer, Frank Review of: Götting, Horst-Peter/ Lunze, Anja (Hrsg.): Überprotektion durch Geistiges Eigentum? (Does Intellectual Property Rights Cause Overprotection?) Nomos Verlagsgesellschaft, Baden-Baden 2009, 235 S., ISBN 978-3-8329-4289-2, Gewerblicher Rechtsschutz und Urheberrecht Internationaler Teil, 59 (8/9), 771-772.

Mueller-Langer, Frank Review of: Axel Gosseries, Alain Marciano & Alain Strowel (eds.): Intellectual Property and Theories of Justice. Palgrave Macmillan, 2008, 277 S., IIC - international review of intellectual property and competition law, 41 (2), 247-250.

Monographies

Mueller-Langer, Frank (2009). Creating R&D Incentives for Medicines for Neglected Diseases. An Economic Analysis of Parallel Imports, Patents, and Alternative Mechanisms to Stimulate Pharmaceutical Research (Gabler Research: Ökonomische Analyse des Rechts). Wiesbaden: Gabler.

Discussion Papers

Jorzik, Nathalie; Kirchhof, Paljana; Mueller-Langer, Frank (2023). Industrial Data Sharing and Data Readiness: A Law and Economics Perspective, Max Planck Institute for Innovation & Competition Research Paper, No. 23-22. DOI

• We study the incentives and welfare properties of industrial data sharing taking into account the data (economy) readiness of companies. We differentiate between two regulatory settings. First, there is no compulsionfor companies to provide data. Companies, which also use the data for other corporate purposes, decide whether to share their data voluntarily. Second, there is a regulatory requirement on the minimum amount of data to be shared by the data provider. We assume that data sharing affects the data provider’s value of the data. The magnitude and sign of this effect have an impact on the optimal investment level of data generation and overall welfare in the different cases under study. Our results suggest that the implementation of a data-sharing policy has ambiguous welfare properties. It has positive welfare properties if (a) the data receiving firm does not pay too much for the data, (b) the data receiving firm benefits enough from the data provider’s data generating effort, and (c) the intensified competition due to data sharing is not too harmful to the data provider. In contrast, it will always have negative welfare properties if the data provider’s minimum amount of data to be shared under the policy is prohibitively high such that no data is created in the first place. Our results also suggest that a positive effect of data sharing on the data-generating company’s value of the data and its data economy readiness positively affect the incentives to share data. Finally, we find that data sharing under a data-sharing policy leads to a lower data quality if the data economy readiness of the data-generating company is too low.
• Forthcoming in: European Journal of Law and Economics

Duch-Brown, Nestor; Gomez-Herrera, Estrella; Mueller-Langer, Frank; Tolan, Songül (2021). Market Power and Artificial Intelligence Work on Online Labour Markets, Max Planck Institute for Innovation and Competition Research Paper Series, No. 22-01.

• We investigate three alternative but complementary indicators of market power on one of the largest online labour markets (OLMs) in Europe: (1) the elasticity of labour demand, (2) the elasticity of labour supply, and (3) the concentration of market shares. We explore how these indicators relate
  to an exogenous change in platform policy. In the middle of the observation period, the platform made it mandatory for employers to signal the rates they were willing to pay as given by the level of experience required to perform a project, i.e., entry, intermediate or expert level. We find a positive labour supply elasticity ranging between 0.06 and 0.15, which is higher for expert-level projects. We also find that the labour demand elasticity increased while the labour supply elasticity decreased after the policy change. Based on this, we argue that market-designing platform providers can influence the labour demand and supply elasticities on OLMs with the terms and conditions they set for the platform. We also explore the demand for and supply of AI-related labour on the OLM under study. We provide evidence for a significantly higher demand for AI-related labour (ranging from +1.4% to +4.1%) and a significantly lower supply of AI-related labour (ranging from -6.8% to -1.6%) than for other types of labour. We also find that workers on AI projects receive 3.0%-3.2% higher wages than workers on non-AI projects.
• Available at SSRN
• Also in: Research Policy Volume 51, Issue 3, April 2022, 104446

Mueller-Langer, Frank; Gomez-Herrera, Estrella (2021). Mobility Restrictions and the Substitution between On-Site and Remote Work: Empirical Evidence from a European Online Labour Market, Max Planck Institute for Innovation & Competition Research Paper, No. 21-26.

• Intensified by the COVID-19 pandemic, online labour markets are at the core of the economic and policy debate about the future of work and the conditions under which we work online. We analyse the effects of an increase in the cost of on-site work induced by COVID-19-related mobility restrictions on the substitution between on-site and remote job postings and between on-site and remote hires. We benefit from the fact that the implementation of stay-at-home requirements varies by country, time and level. We use unique company data from a large European online labour market. We provide empirical evidence for a positive effect of stay-at-home restrictions on job postings and hires of remote work relative to on-site work. Overall, our results suggest that employers are substituting remote employment for on-site employment, while there is no substantial change in overall employment.
• Available at SSRN
• Also published in: Information Economics and Policy, Volume 58, March 2022, 100951

Gomez Herrera, Estrella; Mueller-Langer, Frank (2019). Is There a Gender Wage Gap in Online Labor Markets? Evidence from Over 250,000 Projects and 2.5 Million Wage Bill Proposals, Max Planck Institute for Innovation & Competition Research Paper No. 19-07 2019.

• We explore whether there is a gender wage gap in one of the largest EU online labor markets, PeoplePerHour. Our unique dataset consists of 257,111 digitally tradeable tasks of 55,824 hiring employers from 188 countries and 65,010 workers from 173 countries that made more than 2.5 million wage bill proposals in the competition for contracts. Our data allows us to track the complete hiring process from the employers' design of proposed contracts to the competition among workers and the final agreement between employers and successful candidates. Using Heckman and OLS estimation methods we provide empirical evidence for a statistically significant 4% gender wage gap among workers, at the project level. We also find that female workers propose lower wage bills and are more likely to win the competition for contracts. Once we include workers’ wage bill proposals in the regressions, the gender wage gap virtually disappears, i.e., it is statistically insignificant and very small in magnitude (0.3%). Our results also suggest that female workers’ higher winning probabilities associated with lower wage bill proposals lead to higher expected revenues overall. We provide empirical evidence for heterogeneity of the gender wage gap in some of the job categories, all job difficulty levels and some of the worker countries. Finally, for some subsamples we find a statistically significant but very small "reverse" gender wage gap.
• Available at SSRN

McCabe, Mark J.; Mueller-Langer, Frank (2019). Does Data Disclosure Increase Citations? Empirical Evidence from A Natural Experiment in Leading Economics Journals, JRC Digital Economy Working Paper-02.

• Does data disclosure have an impact on citations? Four leading economics journals introduced a data disclosure policy between 2004 and 2006. We use panel data consisting of 17,135 article citing-year observations from 1996 to 2015 for articles published in these journals. Empirical articles that did not disclose data (46% of the sample) serve as a control group. Evidence for a positive open data citation effect is weak (6% and not statistically significant). On the other hand, the citation impacts of publication are substantial and precisely estimated. Pure theory, hybrid and purely empirical articles enjoy citations benefits of 22%, 32% and 44%, respectively. Our pre- and post-publication citation data allow us to identify the citation effects of data disclosure and publication, while controlling for intrinsic article quality.
• https://ec.europa.eu/jrc/sites/jrcsh/files/jrc115801.pdf

Martens, Bertin; Aguiar, Luis; Gomez-Herrera, Estrella; Mueller-Langer, Frank (2018). The Digital Transformation of News Media and the Rise of Fake News: An Economic Perspective, JRC Digital Economy Working Paper-02.

• https://ec.europa.eu/jrc/communities/sites/jrccties/files/dewp_201802_digital_transformation_of_news_media_and_the_rise_of_fake_news_final_180418.pdf

Mueller-Langer, Frank; Fecher, Benedikt; Harhoff, Dietmar; Wagner, Gert (2018). Replication Studies in Economics: How Many and Which Papers Are Chosen for Replication, and Why?, JRC Digital Economy Working Paper-01.

• We investigate how often replication studies are published in empirical economics and what types of journal articles are eventually replicated. We find that from 1974 to 2014 0.10% of publications in the Top 50 economics journals were replications. We take into account the results of replication (negating or reinforcing) and the extent of replication: narrow replication studies are typically devoted to mere replication of prior work while scientific replication studies provide a broader analysis. We find evidence that higher-impact articles and articles by authors from leading institutions are more likely to be subject to published replication studies whereas the probability of published replications is lower for articles that appeared in higher-ranked journals. Our analysis also suggests that mandatory data disclosure policies may have a positive effect on the incidence of replication.
• https://ideas.repec.org/p/ipt/decwpa/2018-01.html
• Also published in Research Policy, 48(1), 62-83

Mueller-Langer, Frank; Scheufen, Marc; Waelbroeck, Patrick (2018). Does Online Access Promote Research in Developing Countries? Empirical Evidence from Article-Level Data, JRC Digital Economy Working Paper, No. 2018-05.

• Universities in developing countries have rarely been able to subscribe to academic journals in the past. The “Online Access to Research in the Environment” initiative (OARE) provides institutions in developing countries with free online access to more than 5,700 environmental science journals. Here we analyze the effect of OARE registration on scientific output by research institutions in five developing countries. We apply a difference-in-difference estimation method using panel data for 18,955 journal articles from 798 research institutions. We find that online access via OARE increases publication output by at least 43% while lower-ranked institutions located in remote areas benefit less. These results are robust when we apply instrumental variables to account for the information diffusion process and a Bayesian estimation method to control for self-selection into the initiative.
• https://ideas.repec.org/p/ipt/decwpa/2018-05.html
• Also published as Max Planck Institute for Innovation & Competition Research Paper No. 16-14

Gomez-Herrera, Estrella; Martens, Bertin; Mueller-Langer, Frank (2017). Trade, Competition and Welfare in Global Online Labour Markets: A 'Gig Economy' Case Study, JRC Digital Economy Working Paper-05. DOI

• This study focuses on collaborative economy platforms that specialize in purely digital tasks that require no physical delivery or proximity between workers and their clients, which we call Online Labour Markets (OLMs). They have a global reach. There is a debate on job fragmentation and deteriorating working conditions in OLMs. This study emphasizes the economic opportunities and explores (a) the drivers of global trade in digital tasks, (b) the determinants of online wages and (c) the welfare impact of OLMs on workers and employers. This is a case study based on data obtained from a single UK-based OLM. Our findings cannot necessarily be generalised to other OLMs with different characteristics. Using panel data we find that the vast majority of employers are located in high-income countries while many workers are located in low-income countries. Workers in low-income countries are motivated to participate mostly by labour productivity gains and the corresponding higher wages. Workers in high income countries combine opportunities for additional work and income with the benefits of flexible time use and other non-wage benefits. Employers are motivated by wage savings and task unbundling. Despite the global nature of digital OLMs, there is an impression of home bias in hiring. OLMs are heterogeneous markets where about half of all transactions are settled above the lowest price bid. Workers' skills and experience as well as their countries of residence have an impact on the agreed wage and the probability of being hired. Worker quality signaling induces superstar effects and a very uneven distribution of work. Taking into account only the difference between online and offline wages in the countries of residence of workers and employers we estimate that this particular OLM has positive monetized welfare effects, both for workers (17%) and even more so for employers (70%). Unobservable non-monetized benefits such as increased flexibility and savings in transport or migration costs for workers and task unbundling for employers give a further boost to welfare. The extent of unbundling is demonstrated by the very short duration of the average task in this OLM: slightly less than 8 hours. Workers in this case study platform are self-employed and responsible for compliance with regulations in their country of residence.

Mueller-Langer, Frank; Fecher, Benedikt; Harhoff, Dietmar; Wagner, Gert G. (2017). The Economics of Replication, Max Planck Institute for Innovation & Competition Research Paper, No. 17-03.

• Revise-and-Resubmit, Research Policy
• Replication studies are considered a hallmark of good scientific practice. Yet they are treated among researchers as an ideal to be professed but not practiced. To provide incentives and favorable boundary conditions for replication practice, the main stakeholders need to be aware of what drives replication. Here we investigate how often replication studies are published in empirical economics and what types of journal articles are replicated. We find that from 1974 to 2014 less than 0.1% of publications in the top-50 economics journals were replications. We do not find empirical support that mandatory data disclosure policies or the availability of data or code have a significant effect on the incidence of replication. The mere provision of data repositories may be ineffective, unless accompanied by appropriate incentives. However, we find that higher-impact articles and articles by authors from leading institutions are more likely to be subject of published replication studies whereas the replication probability is lower for articles published in higher-ranked journals.
• SSRN

Duch-Brown, Nestor; Martens, Bertin; Mueller-Langer, Frank (2017). The Economics of Ownership, Access and Trade in Digital Data, JRC Digital Economy Working Paper-01.

• https://ec.europa.eu/jrc/sites/jrcsh/files/jrc104756.pdf

Mueller-Langer, Frank; Scheufen, Marc; Waelbroeck, Patrick (2016). Does Online Access Promote Research in Developing Countries? Empirical Evidence from Article-Level Data, Max Planck Institute for Innovation & Competition Research Paper, No. 16-14.

• Under review (sent to referees), Journal of Economic Behaviour and Organization
• Universities in developing countries have rarely been able to subscribe to academic journals in the past. The “Online Access to Research in the Environment” initiative (OARE) provides institutions in developing countries with free online access to more than 5,700 environmental science journals. Here we analyze the effect of OARE registration on scientific output by research institutions in five developing countries. We apply a difference-in-difference estimation method using panel data for 18,955 journal articles from 798 research institutions. We find that online access via OARE increases publication output by at least 43% while lower-ranked institutions located in remote areas benefit less. These results are robust when we apply instrumental variables to account for the information diffusion process and a Bayesian estimation method to control for self-selection into the initiative.
• SSRN
• Also published as JRC Digital Economy Working Paper 2018-05

Mueller-Langer, Frank; Gerstenberger, Michael; Hackinger, Julian; Heisig, Benjamin (2013). A Brief Guide for the Creation of Author-specific Citation Metrics and Publication Data Using the Thomson Reuters Web of Science and Scopus Databases, RatSWD Working Paper Series, No. 228/2013.

• The objective of this guide is twofold. First, it shall enable interested readers to understand and reproduce the process of collecting author-specific citation metrics and publication data from the Thomson Reuters Web of Science and Scopus databases that is adopted in Andreoli-Versbach and Mueller-Langer (2013). Second, it presents the problems faced during the data collection process and the refined method of data collection we adopt to address related concerns. Thereby, it may serve interested readers as a guideline to accurately and efficiently retrieve citation metrics and publication information from Thomson Reuters Web of Science and Scopus in similar endeavors.
• http://www.ratswd.de/dl/RatSWD_WP_228.pdf

Mueller-Langer, Frank; Watt, Richard (2013). Optimal Pricing and Quality of Academic Journals and the Ambiguous Welfare Effects of Forced Open Access: A Two-sided Model, RatSWD Working Paper, No. 223.

• We analyse optimal pricing and quality of a monopolistic journal and the optimality of open access in a two-sided model. The predominant aspect of the model that determines the quality levels at which open access is optimal is the nature of the (non-linear) externalities between readers and authors in a journal. We show that there exist scenarios in which open access is a feature of highquality journals. Besides, we find that the removal of copyright (and thus forced open access) will likely increase both readership and authorship, will decrease
  journal profits, and may increase social welfare.
• http://www.ratswd.de/dl/RatSWD_WP_223.pdf
• Published in Managerial and Decision Economics, Volume 42, Issue 8, Special Issue: Economic Perspectives on the Future of Academic Publishing, December 2021, Pages 1945-1959

Mueller-Langer, Frank; Andreoli-Versbach, Patrick (2013). Leading-effect vs. Risk-taking in Dynamic Tournaments - Evidence from a Real-life Randomized Experiment, Munich Discussion Paper, No. 2013-6.

• Two “order effects” may emerge in dynamic tournaments with information feedback. First, participants adjust effort across stages, which could advantage the leading participant who faces a larger “effective prize” after an initial victory (leading-effect). Second, participants lagging behind may increase risk at the final stage as they have “nothing to lose” (risk-taking). We use a randomized natural experiment in professional two-game soccer tournaments where the treatment (order of a stage-specific advantage) and team characteristics, e.g. ability, are independent. We develop an identification strategy to test for leading-effects controlling for risk-taking. We find no evidence of leading-effects and negligible risk-taking effects.
• http://epub.ub.uni-muenchen.de/15452/

Mueller-Langer, Frank; Andreoli-Versbach, Patrick (2013). Open Access to Data: An Ideal Professed but Not Practised, Max Planck Institute for Intellectual Property & Competition Law Research Paper, No. 13-07.

• We provide evidence for the status quo in economics with respect to data sharing using a unique data set with 488 hand-collected observations randomly taken from researchers' academic webpages. Out of the sample, 435 researchers (89.14%) neither have a data&code section nor indicate whether and where their data is available. We find that 8.81% of researchers share some of their data whereas only 2.05% fully share. We run an ordered probit regression to relate the decision of researchers to share to their observable characteristics. We find that three predictors are positive and significant across specifications: being full professor, working at a higher-ranked institution and personal attitudes towards sharing as indicated by sharing other material such as lecture slides.
• Available at SSRN

Mueller-Langer, Frank; Jorzik, Nathalie (2013). Multilateral Stability and Efficiency of Trade Agreements: A Network Formation Approach, Munich Discussion Paper, No. 2013-3.

• We study the endogenous network formation of bilateral and multilateral trade agreements by means of hypergraphs and introduce the equilibrium concept of multilateral stability. We consider multi-country settings with a firm in each country that produces a homogeneous good and competes as a Cournot oligopolist in each market. Under endogenous tariffs, we find that the existence of a multilateral trade agreement is always necessary for the stability of the trading system and that the formation of preferential trade agreements is always necessary for achieving global free trade. We also find that global free trade is efficient but not necessarily the only multilaterally stable trade equilibrium when countries are symmetric (heterogeneous) in terms of market size. We derive conditions under which such a conflict between overall welfare efficiency and stability occurs.
• Available at SSRN

Mueller-Langer, Frank; Eichberger, Jürgen (2012). On the Welfare Effects of Exclusive Distribution Arrangements, Max Planck Institute for Intellectual Property and Competition Law Research Paper, No. 12-07.

• The regulation of vertical relationships between firms is the subject of persistent legal and academic controversy. The literature studying vertical trade relationships seems to assume that an upstream monopolist prefers downstream competition over exclusive distribution arrangements. We derive precise conditions for when an upstream monopolist prefers competing distribution systems over exclusive distribution in the downstream market. We also show that the welfare effects of downstream competition are ambiguous. A downstream oligopoly may have negative welfare properties compared to a downstream monopoly.
• Available at SSRN

Mueller-Langer, Frank; Watt, Richard (2012). Optimal Pricing and Quality of Academic Journals and the Ambiguous Welfare Effects of Forced Open Access: A Two-Sided Model, TILEC Discussion Paper, DP 2012-019.

• We analyze optimal pricing and quality of a monopolistic journal and the optimality of open access in a two-sided model. The predominant aspect of the model that determines the quality levels at which open access is optimal is the nature of the relationship between readers and authors in a journal. In contrast to previous literature, we firstly show that there exist scenarios in which open access is a feature of high-quality journals. Second, we find that removal of copyright (and thus forced open access) decreases journal profits but has ambiguous social welfare effects.
• Available at SSRN
• Published in: Managerial and Decision Economics Volume 42, Issue 8, Special Issue: Economic Perspectives on the Future of Academic Publishing, December 2021, Pages 1945-1959

Mueller-Langer, Frank (2011). Neglected Infectious Diseases: Are Push and Pull Incentive Mechanisms Suitable for Promoting Research?, Max Planck Institute for Intellectual Property and Competition Law Research Paper, No. 11-10.

• Available at SSRN

Mueller-Langer, Frank; Andreoli-Versbach, Patrick (2011). The Absence of 'Order Effects' in Dynamic Tournaments: Evidence from a Real-Life Randomized Experiment, Max Planck Institute for Intellectual Property and Competition Law Research Paper, No. 11-08.

• Available at SSRN

Mueller-Langer, Frank (2010). An Analysis of the Ambiguous Welfare Effects of Parallel Trade Freedom (Max Planck Institute for Intellectual Property, Competition & Tax Law Research Paper, No. 10-03 ).

• The regulation of parallel trade has become a critical issue in the global trading system, as the welfare effects of parallel trade freedom are generally ambiguous. In this paper we investigate the welfare effects of parallel trade freedom for low, intermediate, and high trade costs and different levels of market size. By analyzing a game played between a domestic monopolistic manufacturer of pharmaceuticals and a foreign exclusive distributor we, first, show that parallel trade reduces the profit of the manufacturer and his incentives to invest in R&D. In addition to this first finding, we show, secondly, that the question as to whether parallel trade freedom has positive or negative welfare properties depends on the level of trade cost and the heterogeneity of countries in terms of market size. In particular, we find that parallel trade freedom has a positive effect on global welfare if countries are sufficiently heterogeneous in terms of market size and if trade costs are intermediate and low, respectively. Surprisingly, this result even holds in a situation where parallel trade freedom implies the closure of the smaller market. If, however, countries are virtually homogenous in terms of market size, parallel trade freedom may be detrimental to global welfare for specific levels of trade costs.
• Available at SSRN

Mueller-Langer, Frank (2008). An Analysis of the Welfare Effects of Parallel Trade Freedom, German Working Papers in Law and Economics,9. Berkeley, California: Berkeley Electronic Press.

• In a double marginalization model which is played between a domestic monopolistic manufacturer of pharmaceuticals and a foreign exclusive distributor, I examine the impact of parallel trade freedom on the manufacturer’s profit. I also analyze its impact on global welfare for low, intermediate, and high trade costs and different levels of heterogeneity of the two countries where the manufacturer and the distributor are located. The model suggests that parallel trade – provided that it is a credible threat – reduces the profit of the manufacturer and thus reduces his incentives to invest in R&D. If, however, trade costs are high, parallel trade is a non-credible threat as it is not a worthwhile business activity for the foreign distributor and thus does not have any impact on the profit of the manufacturer. The model shows that parallel trade has positive welfare properties if the two countries are sufficiently heterogeneous in terms of market size and if trade costs are intermediate and low, respectively. If, however, the countries are virtually homogenous in terms of market size, parallel trade may be detrimental to global welfare for specific levels of trade costs.
• http://www.bepress.com/gwp/default/vol2008/iss1/art9/

Mueller-Langer, Frank (2007). A Game Theoretic Analysis of Parallel Trade and the Pricing of Pharmaceutical Products, German Working Papers in Law and Economics,6. Berkeley, California: Berkeley Electronic Press.

• We develop a simple double marginalization model with complete information, in which an original manufacturer of a pharmaceutical product faces potential competition from parallel imports by a foreign exclusive distributor. The model suggests that parallel imports will never occur in the sub-game perfect Nash equilibrium, as it will always be beneficial for the manufacturer to monopolize the home country by undercutting the price of the reimported pharmaceutical product. However, the question as to whether it is optimal for the manufacturer to charge the monopoly price in the home country depends on the level of trade costs and the level of heterogeneity of the two countries, in terms of market size and price elasticity of demand. For the purpose of further research, this paper suggests the introduction of asymmetric information with regard to local demand functions, in order to explain why parallel trade may actually occur in equilibrium.
• http://www.bepress.com/gwp/default/vol2007/iss2/art6/