Event studies are based on the theoretical framework of efficient capital markets and the notion that security prices include all information available to the market. As a result, announcements made by firms provide to market participants information that can be impounded into the market price. This paper investigates the use of event studies in information systems and accounting information systems research using a three-pronged approach. First, this paper provides a comprehensive survey of research that uses event study methodologies, where the events are announcements made by firms about issues related to information systems, e.g., announcements of the adoption of enterprise resource planning systems and of the effect of security breaches in firms' information systems. Second, this paper summarizes event study methodologies used in prior research, along with some of the key parameters and concerns associated with their implementation. Third, this paper provides remarks on key event study modeling issues, and it offers recommendations to researchers. © 2011 Elsevier Inc.

Researchers have used the stock price reaction to firms' disclosures of investment in information technology to investigate the value of those investments. This paper extends that research to include knowledge management (KM). In particular, we test whether and how KM is valued by market participants by examining the stock market reaction and future performance of companies receiving the "Most Admired Knowledge Enterprise" (MAKE) award, which recognizes companies that excel at KM. MAKE awards are generated based on opinions gathered from experts using the Delphi method, a well-known group decision support tool. We find that MAKE winners: (1) experience positive abnormal returns around the award announcement, (2) report superior operating performance relative to their peers subsequent to the receipt of the award, (3) receive upward analyst forecast revisions following the award, (4) experience a positive upward stock price drift following the award, and (5) that the market has taken time to learn how to process and interpret information useful in valuing KM. Thus, our findings contribute to the literature by finding that market participants value KM and KM apparently positively influences accounting performance indicators. In addition, a unique feature of our study is that we investigate the market's response to information gathered using the Delphi method, an information source not previously investigated in stock price reaction literature. © 2013 Elsevier B.V.