To date, I have been involved in three major streams of research, each involving quite different application domains, referent theories, and research methodologies. Given this variety, the focus of my research may seem diffuse. However, a recurring theme in all my research streams is the understanding of how the design of information systems impacts individuals' behaviors and performance and how to design (or redesign) information systems in order to induce appropriate usage behaviors and/or increased performance. I believe that my experiences with research involving such diversity has helped me look at research problems from multiple perspectives as well as understand and appreciate the strengths and weaknesses of different research approaches with respect to the research questions at hand. Below, I outline a brief description of each research stream, along with a list of publications from each stream.

Business Value of E-Commerce Systems Design

My major stream of research, which was the focus of my dissertation research, investigates the assessment of business value of systems design in the context of electronic commerce. My dissertation, entitled "Measuring the Effectiveness of E-Commerce Website Design and its Impact on Business Value," consists of three essays that offer an in depth analysis of the business value impacts of e-commerce website design. The first essay presents a conceptual framework for understanding the efficacy of systems design for Internet-based selling. Using the conceptualization of online shopping as information processing (i.e., purchase decision making), I characterize the online purchasing process as information foraging, which makes it possible to conceptualize the effectiveness of website design in terms of how well the website enables the consumer to achieve high levels of return on information foraging. I present a framework that identifies purchase decision-making contingencies in the context of three different consumer purchase scenarios. The framework is illustrated and evaluated with reference to mini-cases for each of the purchase scenarios. The results of the mini-case analyses suggest a number of design guidelines for software application development in e-commerce. The second essay examines the measurement of the effectiveness e-commerce website design. The main research questions are: How can we conceptualize and measure the effectiveness of an e-commerce website? Can we identify website design inefficiencies? Using production economics as the theoretical basis, I define and model the concept of website efficiency as customer transaction productivity in transforming inputs (e.g., customers actions in interacting with an e-commerce website) into outputs (e.g., checkout of a basket of products). Based on this modeling approach, I propose a full-cycle methodology for measuring website design efficiency from clickstream data using data envelopment analysis (DEA). The value of the proposed methodology is illustrated by applying it to the evaluation of the website of a real-world e-commerce retailer in the online grocery industry. The third essay validates the above measurement approach by investigating the business value impacts of e-commerce website design. Using econometric and marketing science methods, I empirically assess the business value of website efficiency. Detailed analyses of the performance of customers' website usage from web logs with respect to the customers' purchase transaction histories suggest that effective website usage does in fact lead to value creation in terms of customer value. These impacts were found to be significant above and beyond the impact of customer demographics.

Given the highly complex nature of the research domain, an interdisciplinary approach is inevitable. In this research, I bring together theoretical perspectives from a variety of fields including production economics and management science (technical efficiency), marketing (online consumer behavior), operations management (service production and self service technologies) and human-computer interaction (website usability) to propose a measurement approach for assessing the business value of website design. I have been fortunate enough to be in a position to collect a unique dataset through a research relationship with an Internet-based online grocer. My dataset consists of the web server logs and transaction logs from the online grocer. From this dataset, it is possible to reconstruct all of the website navigation behaviors of all transaction activities of the online grocer's customers for a number of different time periods in which significant website design changes were made. With this dataset, it is possible to evaluate the business value of a systems redesign by investigating the business value accrued at the transaction level through changes in pre- and post-redesign navigation behaviors. I will be targeting papers from my dissertation to leading information systems journals such as Information Systems Research, Management Science, MIS Quarterly, IEEE Transactions on Software Engineering as well as other leading journals from the relevant reference disciplines.

To date, this research stream has produced the following papers:

• With Kauffman, R. J. (2005) "Identifying Website Design Inefficiencies: A Business Value-Driven Approach Using DEA", (Working Paper)
• With Kauffman, R. J. (2004) "A Methodology for Business Value-Driven Website Evaluation: A Data Envelopment Analysis Approach", (Working Paper)
• Hahn, J. and Kauffman, R. J. (2003) "Managing What You Never Could Measure: A Data Mining-Based Approach to Measuring the Business Value of Web Site Design", MISRC Working Paper (WP 03-33) (Full paper in PDF)
• With Kauffman, R. J. (2003) "Return on User Experience: Analyzing the Business Value Impact of E-Commerce Website Design", (Working Paper)
• Hahn, J. and Kauffman, R. J. (2002) "Measuring the Effectiveness of E-Commerce Website Design", Paper presented at the WISE 2002 - Workshop on Information Systems and Economics, Barcelona, Spain, December 14-15, 2002.
• Hahn, J. and Kauffman, R. J. (2002) "Information Foraging in Internet-Based Selling: A Systems Design Value Assessment Framework", in M. Shaw (Ed.), E-Business Management: Integration of Web Technologies with Business Models, New York, NY: Kluwer Academic Publishers, p. 195-230.
• Hahn, J., Kauffman, R. J. and Park, J. (2002) "Designing for ROI: Toward a Value-Driven Discipline for E-Commerce System Design", Proceedings of the 2002 Hawai'i International Conference on System Sciences, Big Island, HI, January 7-10, 2002.
• Hahn, J. and Kauffman, R. J. (2001) "Evaluating Web Site Performance in Internet-Based Selling from a Business Value Perspective", Working Paper (WP-01-02), MIS Research Center, Carlson School of Management, University of Minnesota, Minneapolis, MN.
• Hahn, J. (2001) "The Dynamics of Mass Online Marketplaces: A Case Study on an Online Auction", Proceedings of the CHI 2001 Conference on Human Factors in Computing Systems, Seattle, WA, March 31-April 5, pp. 317-324.
• Hahn, J. and Park, J. (2000) "On the Design of Effective Online Market Interfaces: Focusing on Massive Scale Online Auctions", Proceedings of the 10th Annual Workshop on Information Technology and Systems (WITS 2000), Brisbane, Australia, December 9-10, pp. 217-222.
• Hahn, J. (2000) "Web Usability: A Review of 'Web Navigation: Designing the User Experience' (Book Review)", Electronic Markets - The International Journal of Electronic Commerce and Business Media, 10(1), pp. 57-59.

Human Performance in Systems Analysis and Design

This stream of research started out when I was in my master's program at Yonsei University, Seoul, Korea. This research stream looks at how features of systems development methodologies affect human problem solving behavior and performance in information systems analysis and design. The following research questions have been addressed.

• How do systems analysts perform systems analysis and design and how does the development methodology influence this process?
• How does the diagrammatic representation of the methodology affect how people use diagrams for systems analysis and design?
• In order to deal with complexity of the domain, realistic development projects make use of many diagrams from multiple different perspectives and at multiple levels of abstraction.
• How do systems analysts understand a system with so many diagrams?
• How do expert and novice systems developers differ in terms of the process of designing systems?
• How can we improve systems development methodologies, in terms of both the modeling formalism as well as the prescribed process to improve performance in systems analysis and design?

Theories in the cognitive sciences (e.g., human problem solving and reasoning, diagrammatic reasoning, expertise and expert performance) were mainly used to theorize about and analyze analysts' cognitive processes in systems analysis and design. In terms of research methodology, controlled experiments with detailed protocol analysis were dominant within this stream of research. To date this research stream has produced several publications in top journal and top conference in information systems, computer science, and cognitive science. A list of papers from this stream of research is as follows:

• Kim, J., Hahn, J. and Hahn, H. (2000) "How Do We Understand a System with (So) Many Diagrams: Cognitive Integration Processes in Diagrammatic Reasoning", Information Systems Research, Vol. 11, No. 3, pp. 284-303. (Full paper available at INFORMS PubsOnline)
• Hahn, J. and Kim, J. (1999) "Why are Some Representations (Sometimes) More Effective", In Prabhuddha De and J. I. DeGross (Eds.), Proceedings of the 20th International Conference on Information Systems, Charlotte, North Carolina, December 12-15, pp. 245-259.
• Hahn, J. and Kim, J. (1999) "Why are Some Diagrams Easier to Work With? Effects of Diagrammatic Representation on the Cognitive Integration Process of Systems Analysis and Design", ACM Transactions on Computer Human Interaction, Vol. 6, No. 3, pp. 181-213. (Full paper available at ACM Digital Library)
• Kim, J., Hahn, J. and Lerch, J. (1997) "How is the Designer Different from the User?: Focusing on a Software Development Methodology", Empirical Studies of Programmers 7, p. 69-90, Ablex Publishing.
• Kim, J. and Hahn, J. (1997) "Reasoning With Multiple Diagrams: Focusing on the Cognitive Integration Process", In Proceedings of the 19th Annual Conference of the Cognitive Science Society, p. 376-381, Lawrence Erlbaum Associates.
• Hahn, H., Hahn, J. and Kim, J. (1997) "A Cognitive Engineering Study on the Development of an Object-Oriented Process Modeling Formalism", Proceedings of the 30th Annual Hawai'i International Conference on System Sciences, Vol. 2, p. 199-209, IEEE Computer Society.

Knowledge Management in Electronic Environments

Finally, a third stream of research concentrates on organizational behavior in the context of knowledge management in electronic environments. This stream of research investigates knowledge management from the perspective of organizational communication in computer-supported cooperative work (CSCW) environments for knowledge sharing. Some of the research questions asked in this research stream are:

• How do people share information and knowledge in a computer-mediated environment?
• Why do people share knowledge, especially with people with whom they have never had any prior face-to-face contact?
• Do aspects of the design of electronic communication technologies influence the patterns of communication interaction? If so, how and what aspects are most important in shaping behavioral patterns in communication?
• Do different processes of communication interaction yield different outcomes in terms of knowledge sharing performance?
• How can (or should) we measure performance in a knowledge sharing context?
• How can we design communication/knowledge management technologies for more effective and efficient knowledge sharing?

Theories in organizational behavior and human-computer interaction (e.g., organizational learning, information richness theory and computer-mediated communication) were mainly used to investigate some of the above research questions. In terms of research methodology, field studies involving qualitative interviews with knowledge managers accompanied with extensive longitudinal observation of communication data from various communication technologies (e.g., Usenet newsgroups and email distribution lists) were used. Special purpose data-collecting software agents were also developed for this purpose. To date, this stream of research has produced several papers, which are currently being revised and/or extended for submission to leading information systems or organization science journals (e.g., Information Systems Research, MIS Quarterly, Journal of MIS or Organization Science). A list of papers from this stream of research is as follows:

• Hahn, J., Kannan, K. and Zhang, C., "Markets vs. Communities: An Empirical Analysis in the Knowledge Exchange Context", Working Paper
• Hahn, J. and Subramani, M. R., "A Framework of Knowledge Management Systems: Issues and Challenges for Theory and Practice", In Orlikowski, W. J., Ang, S., Weill, P., Krcmar, H. C., and DeGrosss, J. I. (Eds.) Proceedings of the 21st International Conference on Information Systems, Brisbane, Australia, December 10-13, pp. 302-312, 2000.
• Hahn, J. and Subramani, M. R., "Examining the Effectiveness of Electronic Group Communication Technologies: The Role of the Conversation Interface", Under revision after first review at Journal of Management Information Systems. An earlier version of this paper was presented at the Academy of Management Conference (OCIS Division), Toronto, Canada, August 8, 2000.