In today’s health system, it is widely believed that the best care for individuals is based on the training and experience of professionals. The new rule, on the other hand, could be stated: The best care results from the conscientious, explicit, and judicious use of current best evidence and knowledge of patient values by well-trained, experienced clinicians.

At their best, health care services match knowledge and need. When care does not match knowledge, it may fail to help—either by omission (failing to do what would help) or by waste (doing what cannot help). The health system today is too tolerant of mismatches between knowledge and action; that is, it is too accepting of both omission and waste. As a result, care is too often unreliable, advice and answers are inconsistent, and clinical practice varies without well-founded rationale. The new rule calls for standardization around best practices as appropriate for a given patient or the subpopulation to which a patient belongs. Such evidence-based decision making can free clinicians to make choices that science cannot guide—decisions based on relationship; observation; and the other senses, including touch.

What the new rule calls for is the use of systematically acquired knowledge in all its forms for decision making. The rule does not require that all decisions be based on the results of randomized controlled trials because such results are not always available and because other forms of knowledge exist, such as that derived from epidemiological and population-based data. Neither does the new rule discount clinician experience or the integration of information about a patient’s special circumstances. Rather, it argues that all of these sources of knowledge are relevant and valuable when choosing how to apply evidence. The latter process involves four steps that require training and experience (with organizational and other supports): (1) formulation of a clear clinical question, (2) search for the relevant information from the best possible sources, (3) evaluation of the evidence for its validity and usefulness, and (4) implementation of those findings (Davidoff, 1999).

An emphasis on the use of systematically acquired knowledge derives from a field of study known as evidence-based medicine or, more broadly, evidence-based practice, which evolved during the last decade (Evidence-Based Medicine Working Group, 1992; Muir Gray, 1997; Risdale, 1995; Sackett et al., 2000). The approach often involves systematic examinations of clinical questions that includes a comprehensive review of the literature, standard methods of presenting data, and emphasis on the validity of the research methods. Individual studies are assessed and scored on the basis of their design and execution, including, for example, the selection of patients, the size of the study, and how confounding variables were accounted for (Cook et al., 1997; Lohr and Carey, 1999). Evidence-based practice is described in greater detail in Chapter 6.