Diese Dissertation besteht aus drei Aufsätzen, in denen verschiedene Aspekte von zweiseitigen Märkten untersucht werden. Dabei handelt es sich um Märkte mit zwei verschiedenen Nutzergruppen, von denen jede Netzwerkeffekte auf die jeweils andere Seite ausübt. Im ersten Aufsatz werden die Wechselwirkungen zwischen den traditionellen (offline) Nachfragekanälen und den neuen (online) Nachfragekanälen in der deutschen Zeitschriftenindustrie analysiert. Dabei liegt der Fokus insbesondere auf den Effekten zwischen Offlinewerbung und Onlinewerbung. Das Ergebnis der Schätzung eines dafür entwickelten ökonomischen Modells ist, dass Offline- und Onlinewerbung moderate Substitute füreinander sind. Dies erklärt die Verlagerung von Offline- zu Onlinewerbung, die man in den vergangen Jahren beobachten konnte. Im zweiten Aufsatz wird ein semistruktureller Ansatz zur Messung von Netzwerk-Effekten auf potentiell zweiseitigen Monopol-Plattformen entwickelt. Der Test ist hinreichend, wenn lediglich Daten zum Gesamtumsatz der Plattform zur Verfügung stehen. Sind getrennte Umsatzdaten für die beiden Seiten verfügbar, dann ist der Test sowohl notwendig als auch hinreichend. Der dritte Aufsatz untersucht Mechanismen und Anreize, die die Koordination von Angebot und Nachfrage auf Kreditmärkten ermöglichen, in denen es keine Finanzintermediäre mit eigener finanzieller Beteiligung an den vergebenen Darlehen gibt. Dazu wird der Online-Direktkreditmarkt analysiert, in welchem an die Stelle von klassischen Finanzintermediären ein System von Gruppen tritt. Anhand eines Differenz-in-Differenzen-Ansatzes wird gezeigt, dass Entgelte für die Leiter dieser Gruppen zu adversen Anreizen führen können. Nach Abschaffung der Entgelte differenzieren die Leiter der Gruppen deutlich stärker bei der Auswahl derjenigen Kreditgesuche, die sie als investitionswürdig empfehlen. Gleiches ist zu beobachten, wenn die Leiter der Gruppen selbst zu einem großen Teil an den entsprechenden Darlehen beteiligt sind. / This dissertation investigates various aspects of two-sided markets - markets with at least two distinct user groups each of which exerts inter-group network effects on the other side - in the online world. In the first paper, I examine the interactions between the traditional (offline) demand channels and the new (online) demand channels in the German magazines industry, focusing in particular on the link between offline and online advertising. I find that offline and online advertising are substitutes although not perfect ones. This explains the shift from offline to online advertising observed in recent years. In the second paper, I develop a semi-structural approach to identify network effects on two-sided monopoly platforms without data on prices and quantities. A sufficient test for the existence of network effects is derived when only data on total revenue is available. If separate revenue data is available on the two sides, then the test is both necessary and sufficient. The third paper investigates the certification mechanisms and incentives that enable lending markets to match demand and supply despite the absence of financial intermediaries with skin in the game. The institutional setting for this analysis is the online social lending market, in which potential lenders and borrowers interact directly without a financial intermediary but can create self-organized groups instead. A difference-in-difference approach is used to examine how the same groups behave before and after the exogenously imposed elimination of rewards for the leaders of these groups. Allowing group leader rewards is found to be detrimental for the market outcome. Group leaders become more careful in screening after the elimination of these rewards, and if their loan participation is high, i.e. when they have skin in the game and are thus severely hurt by a borrower default.

Diese Dissertation umfasst sowohl einen theoretisches als auch einen empirischen Beitrag zur Analyse der Messung der gesamten Faktorproduktivität (TFP). Das erste Kapitel inspiziert die bestehende Literatur über die häufigsten Techniken der TFP Messung und gibt einen Überblick über deren Limitierung. Das zweite Kapitel betrachtet Daten, die durch ein Real Business Cycle Modell generiert wurden und untersucht das quantifizierbare Ausmaß von Messfehlern des Solow Residuums als ein Maß für TFP Wachstum, wenn der Kapitalstock fehlerhaft gemessen wird und wenn Kapazitätsauslastung und Abschreibungen endogen sind. Das dritte Kapitel schlägt eine neue Methodologie in einem bayesianischen Zusammenhang vor, die auf Zustands- Raum-Modellen basiert. Das vierte Kapitel führt einen neuen Ansatz zur Bestimmung möglicher Spill-over Effekte auf Grund neuer Technologien auf die Produktivität ein und kombiniert eine kontrafaktische Zerlegung, die von den Hauptannahmen des Malquist Indexes abgeleitet wird mit ökonometrischen Methoden, die auf Machado and Mata (2005) zurückgehen. / This dissertation consists of theoretical and empirical contributions to the study on Total Factor Productivity (TFP) measurement. The first chapter surveys the literature on the most used techniques in measuring TFP and surveys the limits of these frameworks. The second chapter considers data generated from a Real Business Cycle model and studies the quantitative extent of measurement error for the Solow residual as a measure of TFP growth when the capital stock is measured with error and when capacity utilization and depreciation are endogenous. Furthermore, it proposes two alternative measurements of TFP growth which do not require capital stocks. The third chapter proposes a new methodology based on State-space models in a Bayesian framework. Applying the Kalman Filter to artificial data, it proposes a computation of the initial condition for productivity growth based on the properties of the Malmquist index. The fourth chapter introduces a new approach for identifying possible spillovers emanating from new technologies on productivity combining a counterfactual decomposition derived from the main properties of the Malmquist index and the econometric technique introduced by Machado and Mata (2005).

This thesis sheds light on the functioning and characteristics of payment systems to serve as a foundation for understanding the drivers for higher payment system efficiency. Its central goal is to develop insights into the determinants of collective payment choice suitable to lower payment costs to society. So far, the institutional environment, as potential important influence on the payment instrument mix, has not been focused on in the literature. Therefore, particular emphasis is laid on the empirical analysis of the impact of institutional factors on the share of card payments on consumer spending at the point of sale (POS). For this, a unique panel data set is constructed covering the eight most important European payment markets ranked by non-cash transaction volumes. The empirical results allow formulating conditions necessary to achieve a more efficient payment mix. They also form a basis for the assessment of related policy measures with a focus on the SEPA project in terms of their efficiency enhancing effect. Future research could possibly build upon the panel data collected.

This thesis sheds light on the functioning and characteristics of payment systems to serve as a foundation for understanding the drivers for higher payment system efficiency. Its central goal is to develop insights into the determinants of collective payment choice suitable to lower payment costs to society. So far, the institutional environment, as potential important influence on the payment instrument mix, has not been focused on in the literature. Therefore, particular emphasis is laid on the empirical analysis of the impact of institutional factors on the share of card payments on consumer spending at the point of sale (POS). For this, a unique panel data set is constructed covering the eight most important European payment markets ranked by non-cash transaction volumes. The empirical results allow formulating conditions necessary to achieve a more efficient payment mix. They also form a basis for the assessment of related policy measures with a focus on the SEPA project in terms of their efficiency enhancing effect. Future research could possibly build upon the panel data collected.:1 Introduction 1.1 Payment behaviour in selected European countries 1.2 Research question and approach 2 Foundations: Payment systems and markets 2.1 Functioning of payment systems 2.1.1 Payments, market participants and payment system 2.1.2 Payment instruments and methods 2.1.3 Clearing and settlement arrangements 2.1.4 First observations on obstacles to payment systems development 2.2 Network character of payment markets 2.2.1 Theories of networks 2.2.2 Demand-side network effects in payment markets 2.2.3 Two-sided markets and payment cards 2.2.4 Supply-side economies of scale and open access to infrastructure 2.2.5 Obstacles to payment system development 3 Efficiency of payment systems 3.1 Research on payment infrastructure costs 3.1.1 Efficiency of interbank retail payment systems 3.1.2 Efficiency of intrabank payment processing 3.1.3 Factors influencing infrastructure efficiency 3.2 Research on payment instrument costs at the POS 3.2.1 Methodology and classification of the literature 3.2.2 Estimates of payment costs at the POS 3.2.3 Indicative efficiency ranking of payment instruments 4 Research on payment instrument choice at the POS 4.1 Data sources and categorisation of payment choice determinants 4.2 Price characteristics of payment instruments 4.3 Non-price characteristics of payment instruments 4.4 Transaction attributes 4.5 Constraints on payment choice 4.6 Developing an institutional view of payment choice 5 Empirical analysis: Institutional determinants shaping the POS payment mix 5.1 Two-step modelling approach 5.2 Panel construction and exploration of key data series 5.2.1 Panel data collection and overview of variables 5.2.2 Card usage and cash holding 5.2.3 Payment card diffusion and POS terminal density 5.3 European card schemes and markets 5.3.1 Institutional data collection 5.3.2 Description of European card markets 5.3.3 Overview of institutional data series 5.4 Payment decision 5.4.1 Development of the model and possible extensions 5.4.2 Discussion of the regression results 5.4.3 Diagnostic tests 5.5 Sourcing decision 5.5.1 Diffusion of payment cards 5.5.2 Density of POS terminals 5.5.3 Cash holding and availability at ATMs 5.6 Conclusions: Institutional determinants of payment choice 5.6.1 Linking empirical and theoretical analysis 5.6.2 Route for further research 6 Prospects for an efficient European payment mix 6.1 Objectives for establishing a European payment markets 6.2 SEPA for cards regulatory framework 6.2.1 Regulatory ecosystem 6.2.2 Regulatory framework set by European authorities 6.2.3 Standardization industry initiatives 6.3 Remaining obstacles for an efficient payment mix and outlook Appendix 6.3.1 A–1: Credit- and debit-based payment mechanism 6.3.2 A–2: Multilateral settlement: Access, settlement assets and methods 6.3.3 A–3: Statistical properties of variables 6.3.4 A-4: Unit root tests References