Medical information systems are being recognized for their ability to improve patient outcomes. While standards for the economic evaluation of medical technologies were instituted in the mid-1990s, little is known about their application in medical information technology studies. In a review of medical information technology evaluation studies published between 1982 and 2002, we found that the volume and variety of economic evaluations had increased; however, investigators routinely omitted key cost or effectiveness elements in their designs, resulting in publications with incomplete, and potentially biased, economic findings. Of the studies that made economic claims, 23% did not report any economic data, 40% failed to include any effectiveness measures, and more than 50% used a case study or pre- post- test design. Thus, during a time when health economic study methods in general have experienced significant development, there is little evidence of similar progress in medical information technology economic evaluations.