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Prof. Dr. Stephan Aier

Titularprofessor, Geschäftsführer
+41 71 224 3360


  • Unternehmensweite Informationssysteme
  • Digital Platform Ecosystems
  • Unternehmensarchitekturmanagement
  • Data Management und Data Analytics
  • Digitale Transformation
  • Simulation Modeling
  • Forschungsgebiete

  • Digital Platform Ecosystems
  • Enterprise-wide Information Systems
  • Data Management and Analytics
  • Publikationen

    Acquisition of complementors is a prevailing mechanism available to platform owners to leverage digital platforms’ multidimensional growth. Notwithstanding platform owners’ propensity to acquire complementors, little is known about the potential effects of such acquisitions on the non-acquired complementors. While a group of complementors may benefit from an acquisition, others may perceive an acquisition as the platform owner entering into competition with its own complementors. To address this gap, we examine the acquisition of complementors’ effects on the other complementors in the context of a B2B innovation platform whose evolution is considerably influenced by a plethora of acquisitions. As part of an ongoing research project, in this paper we link academic discourses on acquisitions and platform owners’ market entry to derive a set of hypotheses, which we plan to test in the respective B2B innovation platform ecosystem.

    Behavioral experiments are a highly suitable method for testing theories, as they can establish causality while controlling for other confounding factors. However, researchers that aim to conduct and publish such studies face various concerns about the methodological approach. A lack of clarity exists in our field as to which related practices and design decisions are legitimate and accepted. To address this issue, we present a structured literature review that analyzes the designs of 168 behavioral experiments published in the Senior Scholars’ Basket of journals. We find that most experiments are confirmatory, individual-level, between-subjects laboratory experiments. At the same time, we find that some under-represented experiment designs, such as exploratory online experiments, may bear potential for identifying new behaviors and constructing new or proper-to-IS theories. This paper contains an in-depth discussion on the findings and provides decision support to IS researchers that seek to design and publish behavioral experiments.

    By acquiring complementors, digital platform owners can facilitate rapid advances in the evolution of their platform ecosystems. We describe how Salesforce has successfully evolved its platform ecosystem through the acquisition of complementors. Based on insights from the Salesforce case, we provide recommendations for acquiring complementors, aligning acquisitions with the platform owner’s proprietary developments, integrating the acquired complementors and retaining the coherency of the platform’s offerings even after diverse acquisitions.

    Even though organizations may plan for long-term enterprise-wide ob-jectives, they are shaped by local decision-maker’s actions. The latter tend to have conflicting goals, such as short-term and immediate satis-faction of local business needs over organization-wide objectives. While local and diverse decision-making enables specialized products and services, ungoverned behavior may lead organizations that are hard to control and manage. Hence, the challenge is to harness, rather than eliminate decentral autonomy by reaping its benefits while limit-ing its downsides. Pursuing this purpose, this Design Science Research (DSR) study presents the creation and evaluation of a governance mechanism: a nudge-based label. It also contains a set of design fea-tures, which are evaluated quantitatively and qualitatively with expert surveys and discussions. The contributions include design knowledge about labels and the investigation of nudging as an intra-organizational governance mechanism.

    get_appSacha Fuchs, Roman Rietsche, Stephan Aier, Michael Rivera
    More and more employees request feedback from their organizations to develop and learn. This is reflected by a growing number of digital feedback apps which facilitate high-frequency feedback exchange. However, the effect of feedback has hardly been studied on an organizational level due to complexity. Therefore, we strive to analyze organizational feedback exchange with an agent-based simulation model. Concretely, we study the effect of feedback length and feedback frequency on the organizational return on investment (ROI) of feedback exchange. Our study shows that feedback length stays in an inverted U-shape relationship with ROI. Contrarily, feedback frequency is negatively correlated with ROI. When analyzed jointly, two sweet spots arise: one for medium-length, frequent feedback, and the other, for longer infrequent feedback.

    Platform ecosystems are complex ecologies of firms with individual competencies and collective objectives. The sustainable evolution of platform ecosystems is thereby contingent on taking advantage of the individual competencies of the ecosystem’s actors toward obtaining collective objectives. To learn more about platform ecosystem evolution and dynamics, we study Salesforce, a leading and thriving B2B platform ecosystem. We find that the ecosystem’s evolution was closely defined not only by the platform owner’s orchestrating initiatives, but also by its complementors’ and customers’ competencies and particularities. Specifically, we derive three distinct dimensions of evolution, namely the extension of the platform core technology, the extension of the platform’s functional scope, and the industry-specific specialization of the platform. We further identify three cross-dimension levers, namely proprietary developments, acquisitions, as well as partnerships and alliances, which were employed by the platform owner to drive its platform ecosystem’s evolution.

    Firms struggle to meet dynamically changing customers’ needs. One challenge is to navigate a complex search space to find resources needed for innovations that meet customers’ needs. Another challenge is to acquire the resources at lower costs than revenue opportunities to yield profitability. Digital platforms promise to address these challenges better than the market by providing search matching capabilities and modular, reusable resources. We examine whether platforms improve innovation performance and profitability of firms better than the market, as assumed. Using agent-based modeling and simulation, we find that firms perform better in the market when environmental complexity is low. As environmental complexity increases, firms start to perform better on the platform than in the market, specifically when the platform owner remarkably invests in search matching and modularity capabilities. The study advances our understanding of the environmental conditions under which platforms could be superior or inferior to the market.

    This article offers a short retrospective on the research streams about enterprise-wide IS management at the chair of Robert Winter. Both research project streams on analytical integration (data warehousing, information integration etc.) and transactional integration (application integration, enterprise architecture, transformation management) reside in the same understanding of the extended application landscape developed by Robert Winter.

    Successfully innovating in business ecosystems requires firms to tame the complexity in their competitive environment. Firms must be generative enough to meet dynamically changing customer needs and reap profitability from their innovation efforts. Platforms promise to foster both generativity and profitability through their offered capabilities. Employing an agent-based simulation approach in modeling a platform within its ecosystem, we analyze the effectiveness of platform capabilities under varying conditions. We find complexity in the ecosystems to be a contingency for generativity and profitability effects of platforms. When complexity is low, firms are able to successfully innovate on their own without help from platforms. As complexity increases to medium and high levels, however, firms face higher adaptive tension and platform capabilities become more desirable and effective to generate profitable innovations. We thereby challenge the assumption of platforms being disruptive to all types of environments and delineate under which conditions platforms help taming complexity.

    Organizations are utilizing real-time feedback applications as a means to enable and facilitate a feedback environment that enhances employee performance. Extant studies have focused on individual feedback effects, but organizational effects are not well addressed in literature, especially as it relates performance. We investigate how different feedback configurations have an effect on organizational performance through an agent-based simulation. We find that when providing feedback, it is more important to have a combination of medium values for specificity and valence than the one extreme over the other. Furthermore, the greater the time feedback managers invest in the feedback process, the greater the benefit for the overall organization. However, this comes with costs, since providing feedback is not the only task of a manager. Lastly, in environments with high complexity tasks, any feedback even if it is medium on specificity and contains only a limited amount of positivity results in higher payoffs.



    • 1997-2002: Studium des Wirtschaftsingenieurwesens (Dipl-Ing.) an der TU Berlin, Deutschland, Abschluss mit Auszeichnung
    • 2002-2006: Promotion zum Dr-Ing. zum Thema "Integrationstechnologien als Basis einer nachhaltigen Unternehmensarchitektur - Abhängigkeiten zwischen Organisation und Informationstechnologie" an der TU Berlin, Deutschland, Abschluss mit Note 1,0
    • 2016 Habilitation mit dem Thema "Enterprise Architecture Management: Enabling Coordination of Enterprise-Wide Transformation"
    • 2017 Ernennung zum Privatdozenten für Betriebswirtschaftslehre unter Berücksichtigung der Wirtschaftsinformatik



    Kurse auf Assessment-Ebene 

    • seit 2010    Infotools@HSG, Einführung

    Kurse auf Bachelor-Ebene

    • seit 2021: Grundlagen und Methoden der Informatik (University of St.Gallen)
    • 2020: Enterprise Modeling (University of St.Gallen)
    • seit 2013: Informations- und Kommunikationstechnologien (University of St.Gallen)
    • 2008–2012: Objektorientierte Programmierung mit Java (University of St.Gallen)
    • 2000–2002: Grundzüge der Elektronischen Datenverarbeitung (TU Berlin)
    • 1999–2002: Grundlagen des Maschinen- und Apparatebaus (TU Berlin)

    Kurse auf Master-Ebene

    • seit 2020: Enterprise Architecture Management (University of Liechtenstein)
    • 2018–2020: Methoden: Architekturmanagement (University of St.Gallen)
    • 2018–2020: Forschungsmethoden für Geschäftsinnovation (University of St.Gallen)
    • seit  2014: Enterprise Architecture (Reykjavik University)
    • seit  2013: Business Engineering Navigator: Theorie und Werkzeugunterstützung für die integrierte Unternehmens- und IT-Gestaltung (University of St.Gallen)
    • 2009–2011: Integration und Architektur (University of St.Gallen)
    • 2008: Business Information Systems (University of St.Gallen)
    • 2008–2011: Objektorientierte Programmierung mit Java (University of St.Gallen)
    • 2003–2006: Enterprise Application Integration und Service Orientierte Architekturen (TU Berlin)
    • 2002–2006: Grundlagen der Systemanalyse (TU Berlin)
    • 2002–2006: Systemanalyse Projekte (TU Berlin)
    • 2002–2003: Rechnergestützte Systemanalyse (TU Berlin)

    Kurse auf Executive Education-Ebene

    • 2020: Enterprise Architecture in the Era of the Intelligent Enterprise (OpenSAP MOOC, >10'000 participants)
    • 2015: Enterprise Architecture Management (Logistikunternehmen In-house Programm) 
    • 2013: Data Architecture Management (Energieversorger In-house Programm) 
    • 2012/2013: LEAD Enterprise Architecture Program (SAP, The Netherlands) 
    • seit  2008: Executive Master in Business Engineering (University of St.Gallen) 
    • 2007–2009: Enterprise Architecture Management (Logistikunternehmen In-house Programm) 
    • seit  2007: IT-Business Management (University of St.Gallen)  


    • 2020: Living Boundary Models for Coordination in Digital Platform Ecosystems, funded by the Basic Research Fund, University of St.Gallen
    • 2019–2022: Ambidextrous Digital Platforms: Balancing Control and Emergence, funded by the Swiss National Science Foundation
    • 2019–2021: Corporate Agility Navigator, funded by Innosuisse
    • 2019–2020: Guiding the Co-evolution of Digital Platforms and Service Ecosystems: A Simulation-based Research, funded by the Basic Research Fund, University of St.Gallen
    • from 2019: Data Management and Analytics Community, funded by Credit Suisse, DNB ASA, DZ Bank, Erste Bank Group, UBS
    • 2018–2019: Behavioral Enterprise Architecture Management, funded by the Basic Research Fund, University of St.Gallen
    • 2017–2018: Understanding Institutional Mechanisms of Controlling Information Systems Architecture Complexity: A Simulation-based Research, funded by the Basic Research Fund, University of St.Gallen
    • 2017–2018: Architectural Thinking: Harnessing IT Complexity, funded by ABB
    • 2016–2019: Dynamics of Institutional Mechanisms in Enterprise-wide Information Systems Architecture, funded by: Swiss National Science Foundation
    • 2016–2018: A Value Co-creation Language (ValCoLa), funded by: Swiss National Science Foundation, Fonds National de la Recherche Luxembourg
    • 2016: Understanding Institutional Mechanisms of Controlling Information Systems Architecture Complexity: A Simulation-based Research, funded by the Basic Research Fund, University of St.Gallen 
    • 2015: Decentralized Coordination in Complex Information Systems, funded by the Basic Research Fund, University of St.Gallen
    • from 2013–2019: Business Intelligence in Banking Community (BI BC) funded by Commerzbank AG, Credit Suisse AG, Deutsche Bank AG, DNB, DZ Bank, Erste Group AG, UBS AG
    • 2012–2013: DWH 2.0 – Management of Transformation, funded by Swiss Commission for Technology and Innovation, IBM Switzerland, UBS AG
    • from 2011: Competence Center Corporate Intelligence (CC CI), funded by AXA Winterthur, Barmenia Versicherungen, Bundesagentur für Arbeit, Commerzbank, EnBW, Helsana, Raiffeisen Schweiz, RWE, Swiss Post, Swiss Re
    • 2011–2014: A Design Theory for Architectural Coordination of Enterprise Transformation (ACET), funded by: Swiss National Science Foundation, Fonds National de la Recherche Luxembourg
    • 2006–2011: Competence Center Integration Factory (CC IF), funded b AXA Winterthur, Axpo Informatik AG, Barmenia Versicherungen, Credit Suisse, Deutsche Leasing, Deutsche Telekom Laboratories, Finanz Informatik, Munich Re, Novartis International, PostFinance, RTC AG/HP Banking Center Bern, RUAG, SAP, Zürcher Kantonalbank


    2022      Outstanding Contribution as Associate Editor, European Conference on Information Systems (ECIS 2022)
    2021      Best Paper Award, Conference of the Italian Chapter of the AIS (itAIS 2021) 
    2021      Best Paper Award, European Conference on Information Systems (ECIS 2021) 
    2021      Most Innovative Paper Award, Internationale Tagung Wirtschaftsinformatik (WI2021)
    2021      Best Reviewer Nomination, Internationale Tagung Wirtschaftsinformatik (WI2021)
    2016      Best Paper Nomination, European Conference on Information Systems (ECIS 2016) 
    2015      Best Paper Nomination, Hawaii International Conference on System Sciences (HICSS 2015) 
    2013      Junior Scientist Business Innovation Award, University of St.Gallen 
    2011      Junior Scientist Business Innovation Award, University of St.Gallen 
    2010      Best Paper Nomination, International Conference on Design Science Research in Information Systems and Technology (DESRIST 2010)  


    Verband der Hochschullehrer für Betriebswirtschaft e.V.
    Association for Information Systems (AIS) 
    Swiss Chapter of the AIS (CHAIS)


    • Architektonische Herausforderungen in Digitalen Plattform Ökosystemen, 3. IT-Enterprise Architecture Management (EAM) Hybrid-Konferenz, Wien, 14.06.2021
    • Architekturmanagement: Mit Paradoxien und Dilemmata umgehen, Lean EAM-Konferenz, München/online, 28.10.2020
    • Management der Architekturkomplexität: Nudges als Steuerungsinstrumente, 4te Jahrestagung: EAM – Richtungsgeber für die Digitale Transformation, Berlin, 15.5.2019
    • Regeln, Steuerung und Gehorsam oder „einfach mal laufen lassen“: Architekturmanagement in der digitalen Transformation, Lean EAM-Konferenz, München, 7.11.2018
    • Eine Portfoliosicht auf architektonische Steuerungsmechanismen, 48. St.Galler Anwenderforum, St.Gallen, 29.10.2018
    • Data Architecture for the Business Side, Data Management Round Table, Credit Suisse, Zürich, 6.11.2018
    • Architectural Coordination of Enterprise Transformation (ACET), EEWC 2018, Luxemburg, 1.6.2018
    • Was bedeutet es „wirklich“ Management in komplexen Architekturen zu betreiben? EAM – Richtungsgeber für die digitale Transformation, Berlin, 30.11.2017
    • Steuerung komplexer Architekturen, 46. St.Galler Anwenderforum, St.Gallen, 13.11.2017
    • Die Komplexitätsfalle der Digitalisierung … und wie Architekturmanagement damit umgehen kann, Lean EAM-Konferenz, München, 17.10.2017
    • Von digitalen Illusionen, Strohfeuern und Volltreffern – und wie es dazu kommt, IHK Business Outlook: ICT-Konferenz 2017, St. Gallen, 25.04.2017
    • Architectural Thinking: Lösungskomponenten, Deutsche Bahn: SOA Innovation Lab, Frankfurt am Main, 12.10.2016
    • Architectural Thinking: Harmonisierung lokaler Perspektiven, UBS: BI in Banking Community, Zürich, 11.10.2016
    • Architectural Thinking: Warum mehr Architekturmanament nicht zu einer besseren Architektur führt und was wir stattdessen tun sollten, Konferenz: Quo vadis EAM? Berlin, 27.09.2016
    • Enterprise Architecture Management: What it is, why it matters, and what it takes to make it a success, Bayer Business Services, Berlin, 26.09.2016
    • How we lost control: Rolle und Nutzen des Komplexitätsmanagements in grossen BI-Landschaften, DW2015, 24.11.2015, Zürich
    • IT-Management: Agil oder günstig oder beides? Die St.Galler Idee eines modernen Architekturmanagements, Geschäftsleitungsworkshop, IT Post CH, Bern, 17.11.2015
    • Architectural Thinking: EAM nicht nur für Architekten? 42. St.Galler Anwenderforum, St.Gallen, 08.06.2015
    • Architectural Thinking, Architekturtag Commerzbank, Collegium Glashütten, 27.11.2014
    • Informationsversorgung von Unternehmenstransformationen: Wann, was und wie viel? DW2014, Zürich, 18.11.2014
    • Warum Unternehmenstransformationen unausweichlich sind und wie wir damit umgehen, Innovationstag Barmenia Versicherungen, Wuppertal, 25.08.2014
    • Architectural Coordination of Enterprise Transformation, KTH Stockholm, 11.06.2014
    • Wie tief muss die Facharchitektur modelliert werden? Konferenz Facharchitektur in Banken, Leipzig, 05.05.2014
    • Verhinderer oder Gestalter: Sollten wir die Rolle des Architekten weiter entwickeln? 41. St.Galler Anwenderforum, St. Gallen, 24.03.2014
    • BI als Transformation: Systematisches Management von Transformationen, DW2013, Zürich, 12.11.2013
    • Kaffeesatzlesen oder systematische Steuerung? Kennzahlengetriebenes Management von BI-Landschaften, DW2013, Zürich, 11.11.2013
    • Entwicklungsstufen des Unternehmensarchitekturmanagements, Opening Keynote, Swiss IT Intelligence Community (SITIC): Strategy & Enterprise Architecture, PricewaterhouseCoopers AG, Zürich, 12.06.2013
    • Erfolg von Outsourcing, Steinbeiss Unternehmerforum, Stuttgart, 22.03.2013 Wie werden unternehmensweite Intelligence-Infrastrukturen wirklich wirksam? DW2012, Zürich, 12.11.2012
    • Jenseits von Methoden und Modellen: EAM in unterschiedlichen Unternehmenskulturen erfolgreich machen, Opening Presentation, ITAMKO: IT-Architektur-Management-Konferenz 2012, Vienna, 17./18.10.2012
    • Referenzarchitekturen – Brauchen wir sie, und wenn ja, wie viele? Opening Keynote, Swiss IT Intelligence Community (SITIC): Topic Forum on Technical and Functional Reference Architectures, Postfinance, Zofingen, 20.09.2012
    • Jenseits von Architekturframeworks: Was sollte eine Organisation mitbringen, um EAM verkraften zu können? EAM Community Schweiz, Zurich, 19.09.2012
    • EAM wirksam machen: Warum EAM kein Nischenprodukt sein kann und was es ausser guten Modellen und Methoden braucht, 36. St.Galler Anwenderforum, St. Gallen, 04.06.2012
    • What’s right and what’s wrong with Enterprise Architecture, Opening Keynote, 6th Enterprise Architecture Management Conference 2011, Marcus Evans, Berlin, 23./24.05.2011
    • (IT) Service Management und (Enterprise) Architecture: Ein akademischer Blick auf die Themen „Run the Business“ und „Change the Business“, Opening Keynote, Swiss IT Intelligence Community (SITIC): Topic Forum on Architecture Management & ITIL, Zürcher Kantonalbank, Zurich, 11.03.2010
    • Nutzen und Gestaltung der Unternehmensarchitektur, Deutsche Kongress: Unternehmensarchitektur, Frankfurt/Main, 21.04.2009 Gute Architektur trotz oder wegen Standardsoftware?, 10. Architekturforum der Capgemini sd&m, Zurich, 11.05.2009
    • Serviceorientierung in Unternehmensarchitekturen: Die „richtige“ Transparenz als Basis von Flexibilität und Agilität, Berner Architekten Treffen, Bern, 12.06.2009
    • Planung der Unternehmensarchitektur und Unternehmensarchitektur als Planungsgrundlage, Deutsche Kongress: Unternehmensarchitektur, Zurich, 08.09.2009
    • Enterprise Architecture: Infrastruktur für Business Innovation, 20 Jahre IWI-HSG, St. Gallen, 18.09.2009
    • Unternehmensarchitekturen serviceorientiert gestalten: Die passende Dosis Transparenz für mehr Flexibilität und Agilität, Capgemini sd&m AG: SOA – Von der Theorie zur Praxis, Munich, 07.10.2009
    • Wozu Unternehmensarchitekturen gut sind – und wozu nicht, Deutsche Kongress: IT-Architektur, Frankfurt/Main, 20.02.2008
    • Wert-und stakeholderorientierte Gestaltung der Unternehmensarchitektur: Wozu Unternehmensarchitekturen gut sind – und wozu nicht, Deutsche Kongress: Unternehmensarchitektur, Zurich, 09.09.2008
    • A Stakeholder Based Approach to EA Engineering, The Open Group Conference, Munich, 22.10.2008
    • IT-Architekturmanagement und Unternehmensarchitektur, IQPC: IT-Architekturmanagement, Cologne, 05.12.2006
    • Planung und Flexibilität von IT-Architekturen, IIR, Frankfurt/Main, 04./05.07.2005
    • EAI und Architektur – empirische Befunde, Dritter EAI-Expertentag, Berlin, 25./26. November 2004
    • EAI – Der zweite Schritt: Voraussetzungen und Elemente flexibler Architekturen, EAI-Forum, Mainz, Mai 2004

    Weitere Informationen

    Stephan Aier ist Titularprofessor und Ständiger Dozent an der School of Computer Science der Universität St.Gallen (SCS-HSG) und Geschäftsführer des Instituts für Wirtschaftsinformatik (IWI-HSG). Am IWI-HSG ist er Co-Leiter der Architectural Coordination Group. Er ist Diplom-(Wirtschafts)-Ingenieur (2002) und promovierte sich 2006 zum Dr.-Ing. an der TU Berlin. Im Jahr 2016 habilitierte er und wurde 2017 zum Privatdozenten, 2020 zum Titularprofessor und 2021 zum Ständigen Dozenten der Universität St. Gallen ernannt.

    In anwendungsorientierten Forschungsprojekten u. a. mit AXA Winterthur, Credit Suisse, Deutsche Telekom, EnBW, Motorola, HP, IBM, Munich Re, Novartis, Post CH AG, Finanz Informatik, RUAG, RWE, Swiss Re, UBS, Barmenia und weiteren wurden die theoretischen Arbeiten praktisch angewendet. Stephan ist Autor von mehr als 150 Publikationen in den Bereichen Architektur, Integration und Plattformen. Er ist neben seiner Arbeit in der grundständigen Lehre sowie der Executive Education regelmässig Vortragender auf Konferenzen und Seminaren für Praktiker.