28 May 2026

Photo: UHH Business School

Read about the theses defense in April and May here.

Levent Uyar, Dissertation Defense on May 8

Title and Topic of the Dissertation:

Managing Market Dynamics of Digital Media Streaming Platforms – Empirical Research on Music Streaming

By focusing on the music industry, the dissertation investigates how digital streaming platforms are transforming the media industry technologically, economically, and culturally. At its core is the question of how platforms, as central intermediaries, change market structures with regard to content, value creation, and consumption—and what opportunities and risks arise from this for different market participants.

The cumulative dissertation comprises three empirical projects: The first, published project examines interdependencies between smart speakers and music streaming services, particularly with regard to potential lock-in effects within integrated platform ecosystems. The second project explores the role of payout models of digital streaming platforms from the perspective of consumers and examines resulting consequences for the industry. The third project analyzes music consumption in the global streaming market and investigates, in particular, the influence of linguistic distance as a dimension of product–market fit on the international success of songs.

The dissertation is based on survey data, experimental data, and extensive market data, and contributes to a better understanding of digital platform markets through empirical analyses. In addition, it provides practice-relevant implications for platform operators, suppliers, and policymakers.

Advisors:

Prof. Michel Clement and Prof. Jan Recker

My experience at the School:

The Business School has provided me with important impulses for my academic and personal development, particularly through access to international conferences and opportunities for methodological training. At the same time, the close and interdisciplinary exchange with industry partners and policymakers has helped to address and discuss practice-oriented and socially relevant research questions.

My future plans:

I plan to continue my career at the intersection of technology, marketing, and data-driven business models, with a particular interest in strategic questions in digital companies.

Oliver Schacht, Dissertation Defense on April 30

Title and Topic of the Dissertation:

Essays on Causal Machine Learning: Methodological Advances and Applications in Business Analytics.

It encompasses several studies at the intersection of machine learning and causal inference. In short: While machine learning excels at making predictions (e.g., “How much of product X will I sell tomorrow?”), the business world also requires methods that answer questions about interventions. For example, if I’m faced with the question “How much would I sell if I ran an ad today?” or “Which of these ads will attract the most customers?”, the naive application of machine learning quickly reaches its limits. Biased and inaccurate estimates from observational data can lead to false conclusions. In my dissertation, I focus on algorithms that establish causal relationships to estimate effects for such “counterfactual” questions.

Advisor:

Prof. Martin Spindler

My experience at the School:

I am very grateful to the School for the support I received during my dissertation work. I particularly appreciated the trusting and supportive relationship between researchers, the administration, and students, as well as the positive and friendly atmosphere in the department. For summer schools and conferences, I was able to benefit from travel funds and support for early-career researchers. I am very grateful to my advisor, Prof. Dr. Martin Spindler, for his trust and our close collaboration.

I hope that the School will continue to maintain high standards for research, teaching, and the development of early-career researchers in the future.

My future plans:

Lie wherever the intersection of data, AI, and applications is needed. And perhaps one day in a professorship at a university of applied sciences, as I have greatly enjoyed teaching at the School.

Philipp Schwarz, external candidate, Dissertation Defense on April 30

Title and topic of the dissertation:

Essays on the Application of Causal Methods in Production Systems

The objectives were (1) to investigate the applicability of causal methods in production and (2) to further develop these methods based on insights from practical experience. Specifically, topics from semiconductor manufacturing in the areas of production and power supply were examined. On the practical side, causal data-driven models were developed to evaluate and optimize rework strategies with the ultimate goal of increasing yield. Since manufacturing processes depend on a reliable power supply, causal methods for explaining power spikes were also investigated. In addition to applying DoubleML in a new environment, this work yielded insights and further developments in the areas of “Causal Root-Cause Analysis” and “Regression Discontinuity Designs.”

Advisors:

Prof. Martin Spindler (University of Hamburg), Prof. Martin Weiß (OTH Regensburg), and Dr. Johannes Oberpriller (ams-Osram)

My experience at the School:

The dissertation was structured as an industry dissertation in cooperation with AMS-Osram and was accordingly funded by AMS-Osram. This means that during the dissertation, I spent most of my time working on-site in Regensburg, and I am therefore indebted to my colleagues for the constructive exchange and for creating an environment in which I could conduct creative research on the topics of my dissertation.

My experiences with the School are therefore limited, apart from a few in-person interactions, primarily to the online world. However, the few times I was on campus were marked by warm encounters, shared trips to the cafeteria, and inspiring exchanges. I would also like to highlight the professional support I received on administrative matters from the PhD Office, particularly from Ms. Thoma.

My future plans:

Toward the end of my dissertation, I was offered a position as a data scientist at AMS-Osram, which I started in February.

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