someone choose between a treatment that would give many more years of life with major incapacitation and a treatment that would give fewer years of life with full function. For example, treatment success or failure for prostate cancer has historically been assessed by the clinical outcome of whether the patient died from prostate cancer. However, functional status measures would incorporate other treatment outcomes, such as the patient's urinary, sexual, and bowel function (Litwin et al., 1995). Functional status assessment often includes the degree to which disease limits one's ability to participate fully in activities of daily living. Depending on the type of cancer and phase of illness, such activities could include going to work or caring for children. In patients with more advanced disease, however, assessment of whether they are able to go to the market for groceries or to bathe or dress themselves may be more relevant.
Performance status is a measure of functional status often used in oncology clinical trials. The Karnofsky Performance Status (Karnofsky and Burchenal, 1949) is a rating of patients' functional status that has been used in clinical trials since 1949 (Grieco and Long, 1984). The rating is performed by a physician or nurse. It has been found to be a strong predictor of survival in some patient populations, most notably patients with lung cancer. However, it covers only one aspect of quality of life—physical performance—and, although significantly correlated with quality of life, accounts for less than 50 percent of the variability in patients' own ratings of their quality of life. Although clinician-rated measures have value, the field is moving more toward the use of patients' assessments of functional status and quality of life (Reifel and Gantz, in press), which are preferable models for quality assessment. Examples of patient-based measures include the Cancer Rehabilitation Evaluation System (CARES) (Ganz et al., 1992b; Schag and Heinrich, 1990), the Functional Living Index-Cancer (FLIC) (Schipper et al., 1984), and the Breast Cancer Chemotherapy Questionnaire (BCQ) (Levine et al., 1988).
Consumer satisfaction refers to patients' feelings about the care they receive and is generally measured by patient surveys. There is a relationship between satisfaction and adherence to treatment regimens. Patients who are satisfied are more likely to take their antibiotics properly (Bartlett et al., 1984), to follow treatment recommendations (Hsieh and Kagle, 1991), and to return for follow-up visits (Deyo and Inui, 1980). Thus, the physician has an incentive to please his or her patients as part of the treatment—so that they will be more likely to follow the physician's advice. Furthermore, dissatisfaction with care can lead patients to switch clinicians and health care institutions (Reichheld, 1996; Rubin et al., 1993; Young et al., 1985).
Although consumers are the best source to evaluate their interpersonal care, one limitation of satisfaction ratings is that consumers cannot always tell if the care was appropriate or technically good (Aharony and Strasser 1993); research has not shown a consistent relationship between consumer satisfaction and technical quality of care (Cleary and McNeil, 1988; Davies and Ware, 1988; Hayward et al., 1993). A kind and caring physician may provide care that is technically poor (Aharony and Strasser, 1993). Also, consumer satisfaction may vary with expectations. For example, patients who have a history of poor access to health care may be so appreciative when they actually see a physician that they may report high satisfaction regardless of how well care was delivered. Therefore, it is best not to rely on satisfaction ratings to measure technical quality.