istics (e.g., insurance type, illness profile), and community characteristics (e.g., per capita hospital beds, transportation system, environmental risks). Structural measures specifically related to cancer quality could include the availability of a multidisciplinary cancer center, a bone marrow transplant unit, or psychological support services.

Structural characteristics are often necessary to provide good care, but they are usually insufficient to ensure excellent quality. The best structural measures are those that can be shown to have a positive influence on the provision of care (process quality) and on patients' health (outcomes), although this relationship has not been found for most measures (Brook et al., 1990).

Measures of structural quality have long been the key component in accreditation procedures. Various independent organizations accredit hospitals or health plans based on a set of criteria that generally focus on structural measures such as appropriate capacity for the covered patient population. In recent years, accreditation organizations have also been incorporating process and outcome measures into their accreditation procedures.

Process Quality

Process quality refers to what providers do for patients and how well they do it, both technically and interpersonally. Technical process refers to whether the right choices are made in diagnosing and treating the patient, and whether care is provided in an effective and skillful manner. Whether care is effective can be judged according to evidence from good studies (e.g., clinical trials) that show a link between a particular process and better outcomes. Quality is often measured according to appropriateness criteria or professional standards, but these may or may not conform to available evidence of effectiveness. The quality of evidence is itself rated according to aspects of the study's design and conduct. Reported "levels" of evidence are often used to evaluate the strength of clinical recommendations (see Box 4.1).

An intervention or service (e.g., laboratory test, procedure, medication) is considered appropriate if the expected health benefits (e.g., increased life expectancy, pain relief, decreased anxiety, improved functional capacity) exceed the expected health risks (e.g., mortality, morbidity, anxiety anticipating the intervention, pain caused by the intervention, inaccurate diagnoses) by a wide enough margin to make the intervention or service worthwhile (Brook et al., 1986). Some also distinguish a subset of appropriate care that they term necessary or crucial care. They consider care necessary if there is a reasonable chance of a nontrivial benefit to the patient and if it would be improper not to provide care. In their view, such care is important enough that it might be considered ethically unacceptable not to offer it (Kahan et al., 1994; Laouri et al., 1997). Criteria of appropriateness can be used to measure the overuse of care, which occurs when expected risks exceed expected benefits (which is a problem because of treatment complications and wasted resources), and the underuse of care, which occurs when people are not receiving care that is expected to improve their health.

A good example of the use of process measures can be found in the 1988 General Accounting Office (GAO) assessment of the use of seven "breakthrough" cancer treatments in the United States from 1975 to 1985 (e.g., adjuvant chemotherapy for breast cancer) (USGAO, 1988). All of the treatments had been proven to extend patients' survival in controlled experiments, and for many, the evidence had been available for several years. Data for 1985 show considerable variation in use of these innovative therapies (Table 4.1). The results illustrate the



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