for cases in which myocardial infarctions actually occurred, and the package quite accurately suggested the possibility of that diagnosis, as well as other potentially devastating illnesses that apparently had not been seriously considered.
Chart Checker's benefits are so well demonstrated that in certain instances it has led to an across-the-board 20 percent reduction in malpractice insurance premiums for physicians. In Massachusetts, for example, this reduction in premiums (amounting to $2,400 or more per physician) became effective in July 1990 for all emergency room physicians who regularly use Chart Checker (Blau, 1990). This software is representative of many clinical decision support systems that can be expected to evolve in the near future. Such tools cannot be used by health care professionals, however, until clinical data are captured in machine-readable form. In short, the CPR must come first.
The problem-knowledge coupler (PKC) is another personal computer-based system designed to assist clinicians in organizing patient data in a variety of care settings (Weed, in press). Weed's system permits the clinician to build a computer-based, problem-oriented patient record; it also uses medical knowledge derived from the literature to provide the clinician with timely suggestions and information specific to the symptoms or problems of the current patient to guide and assist the clinician's decision making. Thus, the PKC presents a nearly complete list of potential causes of a patient's reported problems. Only a few topics in medicine have been covered so far, however, because many couplers have yet to be written.
The PKC is designed to provide practitioners with information they need from the literature when they need it. At the moment, the system supplies references to highly relevant, targeted articles that have been searched beforehand and are directly associated with the patient's problems. Some of the system's architects have proposed that a ready link to MEDLINE at the NLM is the solution to answering clinicians' questions near the time of the patient encounter. Currently, however, that notion may be unrealistic because the time required to formulate and perform an adequate bibliographic search is measured in minutes, not seconds.
Decision support systems for health care have been successfully demonstrated in recent years, but they too lack a common standard for representing the knowledge they contain, thus limiting exchanges of their contents (Pryor et al., 1984; Miller et al., 1986). As special medical knowledge databases