Assessing technical performance at diverse ambulatory care sites.

The purpose of the large study reported here was to develop and test methods for assessing the quality of health care that would be broadly applicable to diverse ambulatory care organizations for periodic comparative review. Methodological features included the use of an age-sex stratified random sampling scheme, dependence on medical records as the source of data, a fixed study period year, use of Kessner's tracer methodology (including not only acute and chronic diseases but also screening and immunization rates as indicators), and a fixed tracer matrix at all test sites. This combination of methods proved more efficacious in estimating certain parameters for the total patient populations at each site (including utilization patterns, screening, and immunization rates) and the process of care for acute conditions than it did in examining the process of care for the selected chronic condition. It was found that the actual process of care at all three sites for the three acute conditions (streptococcal pharyngitis, urinary tract infection, and iron deficiency anemia) often differed from the expected process in terms of both diagnostic procedures and treatment. For hypertension, the chronic disease tracer, medical records were frequently a deficient data source from which to draw conclusions about the adequacy of treatment. Several aspects of the study methodology were found to be detrimental to between-site comparisons of the process of care for chronic disease management. The use of an age-sex stratified random sampling scheme resulted in the identification of too few cases of hypertension at some sites for analytic purposes, thereby necessitating supplementary sampling by diagnosis. The use of a fixed study period year resulted in an arbitrary starting point in the course of the disease. Furthermore, in light of the diverse sociodemographic characteristics of the patient populations, the use of a fixed matrix of tracer conditions for all test sites is questionable. The discussion centers on these and other problems encountered in attempting to compare technical performance within diverse ambulatory care organizations and provides some guidelines as to the utility of alternative methods for assessing the quality of health care.