A 3-week-old infant awoke with a fever. He was taken to the doctor who noted that the child was irritable. The doctor took him to the hospital where a resident performed a spinal tap, started an intravenous (IV) line, and ordered antibiotics. The entire drama, from entering the doctor's office to infusion of ampicillin, took 2 hours. The doctor was sued for malpractice. Expert witnesses for the plaintiff testified that he had deviated from the standard of medical care by taking too long to administer antibiotics, which, in their view, ought to have been given within 30 minutes. Expert witnesses for the defense testified that 2 hours to administer antibiotics in this case was within the standard of care. What ought to be the response of the pediatric community to discrepant expert testimony such as this? One possible response is nothing. Lawyers from both sides will find expert medical witnesses who articulate positions favorable to their clients (as they did in this case), and the truth will emerge after vigorous cross-examination. This, we suggest, is inadequate. We believe that some expert opinions can be viewed as better than others. That is, some opinions describe the standard of medical care correctly while other expert opinions are (to put it charitably) idiosyncratic, failing to depict accurately the skill and care ordinarily administered in comparable situations. Currently, jurors are informed about the standard of care by expert witnesses, who rely on their own medical knowledge and experience. However, a huge body of literature demonstrates that recollections of individual experience are inevitably flawed, and flawed in a nonrandom direction (the Monday morning quarterback phenomenon). Consider the infant with meningitis. When experts in pediatric emergency medicine and pediatric infectious diseases (ID) were asked about the median time from emergency room (ER) presentation to administration of antibiotics in a child with suspected meningitis, their opinions were wrong and slanted toward the outcome known to be desired (namely, a shorter elapsed time). ER physicians (median estimated time to antibiotic administration [AB-TIME] = 46 minutes) and ID physicians (median estimated AB-TIME = 80 minutes) consistently underestimated the actual median value of AB-TIME determined by chart review (120 minutes). From the judicial perspective such potential flaws in expert testimony are assumed to be equally distributed among experts. All admissible evidence is a priori of equal weight until a jury decides otherwise. The standard of medical care is created anew by expert testimony in each individual case, disappearing, like Brigadoon, upon resolution of the dispute. However, to anyone but a lawyer, the standard of medical care must exist as something outside the courtroom testimony of experts, and if it does exist, it should be easily described so that expert testimony can be judged more (or less) accurate in depicting it. We contend that medical care is not a single behavior that conforms to or deviates from an idiosyncratic and retrospectively determined standard, but rather a distribution of behaviors in response to a variety of medical circumstances. For a given scenario, each of several possible responses can be ascribed a relative frequency based on empirical data, and the consequent normal curve depicts the totality of medical care. Substandard care then falls out neatly as behaviors lying outside the large majority of cases. Juries would be empowered (as they are currently) to determine exactly where on this curve substandard care lies, but at least the debate would share the same description of reality. Recent US Supreme Court guidelines regarding expert testimony provide an opportunity to expand the use of databases in medical negligence cases. The Court restricted expert testimony to "scientific knowledge ... based on generating hypotheses and testing them to see if they can be falsified ... (ABSTRACT TRUNCATED)