Carl H. Slater

A method of developing and weighting explicit process of care criteria for quality assessment.

The use of explicit criteria to evaluate how well processes of care conform to accepted standards is a key method of quality assessment. Synthesizing four decades of literature, we devised an inexpensive, 6-step method of developing reliable, content-valid, explicit process criteria. This paper describes the method using a set of congestive heart failure criteria. In step 1 of the Criteria Development Method, criteria are derived from state-of-the-art clinical literature. In step 2, criteria are refined by expert panels. In this study, panelists refined the items by mail in a three-round Delphi process. In step 3, decisions about unit-or differential item weighting are made; we derived differential item weights from the panelists third-round ratings. Step 4 consists of flagging items which may yield little information, i.e., consensus items of low import, and nonconsensus items. Numeric flags were computed using third-round median ratings and their interquartile ranges. Selection of a scoring method to summarize scores and communicate results is done in step 5. In step 6, chart reviewers are trained, inter-rater reliability is measured, and items with poor reliability are culled. This straightforward developmental method can be used to devise explicit process criteria for use in ambulatory or hospital settings and to evaluate care delivered by different types of providers. The method yields reliable criteria representing accepted standards of current clinical practice. This high content validity is a sine qua non for convergent and predictive validity, both of which must be demonstrated in empirical studies in which the criteria are compared against external yardsticks.

The validity of single-item, self-assessment questions as measures of adult physical activity

Individual energy expenditure (kcal/kg/day) was calculated from a detailed set of questions from the Health Promotion and Disease Prevention Supplement of the 1985 National Health Interview Survey. Responses to three single-item, self-assessment questions were compared to the energy expenditure variable to test criterion validity. Spearmans correlation coefficient revealed moderate correlations between energy expenditure and corresponding levels of self-assessed leisure-time physical activity for each single-item question (r = 0.14 to 0.41). For purposes of measuring prevalence of physical activity, the energy expenditure variable was used to categorize individuals into activity levels. The single-item questions were found to have Spearmans correlations with the categorical measures ranging from 0.11 to 0.37 for leisure-time activities. Generally higher correlations were found for males and younger age groups (18-34 years). The relationships were interpreted as being weak relative to an expected correlation of 0.75 for criterion validation. However, the single-item questions show promise for obtaining proxy estimates of the degree of leisure-time physical activity in a population.

The independent contributions of socioeconomic status and health practices to health status.

The objective of this study was to determine whether the much-repeated finding of a relationship between socioeconomic status and health status is explained by individuals health practices. The investigation was carried out using data tapes from the 1977 Health Interview Survey in which a one-third subsample of adults was asked a series of questions related to the seven nonmedical health practices identified in the Alameda County Study. The group selected for analysis comprised 15,892 white, responding adults. With age controlled statistically, perceived health status was found to be associated with socioeconomic status, whether the indicator was educational level, family income, or occupation, and to number of positive health practices. When number of health practices, in addition to age and other socioeconomic indicators was controlled for, the association was still positive and significant. The finding of an independent contribution by socioeconomic status to health status emphasizes that individual health habits are not the only influence on health status.

Avoidable hospitalizations and socio-economic status in Galveston County, Texas

Population-based hospitalization rates for preventable conditions are derived for a low-income population in Galveston County, Texas using discharge data from four area hospitals and demographic data from the U.S. Census. Comparisons are made with similar rates for the general populations of two eastern states (Maryland and Massachusetts) and New York City. Results support the hypothesis that low-income persons lack access to primary care, leading to higher rates of hospitalization for preventable conditions. Alternative explanations for differences found are examined.

Problems in estimating the prevalence of physical activity from national surveys

Health policy in the United States has paid scant notice to physical activity until recently. This current policy focus on physical activity has revealed not only that there is less than adequate data about it but also that the single survey questions used for the purpose of measuring its prevalence should be interpreted carefully. A case in point is the example presented in this article, which gives estimates of physical activity prevalence levels for women of child-bearing ages from several National Center for Health Statistics (NCHS) surveys. The amount of physical activity reported, and thus the proportion of women at risk for various diseases due to limited activity, depends on how the question is asked and the type of responses offered as options. Various questions used in three different NCHS surveys produced prevalence estimates of limited physical activity levels ranging from 3.9 to 39.1%. These findings have important implications for survey assessments of physical activity at all policy levels.

A reassessment of the additive scoring of health practices.

Over the past 20 years, investigators have been refining the connection between behavioral practices, popularly known as health habits, and health status. Repeated study has demonstrated that the number of healthful practices, regardless of which ones are adopted, provides a reliable predictor of mortality. Few studies, however, have questioned the validity of summing such diverse practices as smoking and physical activity together to form a single practice score. The purpose of this study was to raise some questions about this widely adopted scoring procedure and to reassess the problems connected with its use. Data are drawn from the Texas Behavioral Risk Factor Survey of 1982. The approach contrasts practice profiles formed from all possible combination of practices, representing full information about them, and the scores produced by collapsing practices onto a single dimension. Special attention is given to the meaningfulness of the information lost in the scoring process and to the implications this may have for the health practice-to-health status relationship

Agreement of self-reported and physiologically estimated fitness status in a symptom-free population

A population of 204 symptom-free clerical and white-collar employees who volunteered for a corporate-based health promotion program was studied to determine agreement between self-reported and physiologically determined fitness status. Physiologic fitness was estimated using exercise treadmill performance. There were statistically significant differences between self-reported and treadmill-estimated fitness status. The study population rated their fitness substantially higher than that estimated by treadmill performance. Self-reported fitness was found to be poorly correlated with physiologic fitness, indicating independent distributions. These relationships persisted across gender. The results question the use of self-reported estimates of physical health in health services research.

The Houston Vision Assessment Test (HVAT): An assessment of validity

PURPOSE. Cataract surgery is one of the most successful procedures in medicine, and outcome is typically measured by a single factor – improvement in visual acuity. Health-related functional outcome testing, which quantifies the patients self-reported perception of impairment, can be integrated with objective clinical findings. Based on the patients self-assessed lifestyle impairment, the physician and patient together can make an informed decision on the treatment that is most likely to benefit the patient. METHOD. A functional outcome test (the Houston Vision Assessment Test – HVAT, copyrighted 1990, 1992) was evaluated in a cataract population of 149 patients from seven study centers. Test results were correlated with objective ophthalmic endpoints. The HVAT divides an estimated total impairment into subcomponents of Visual Impairment (correctable by cataract surgery) and non-visual Physical Impairments (co-morbidities not affected by cataract surgery). RESULTS. In this prospective study, the average Visual Impairment score improved by 19 points (65%) following cataract extraction (the mean HVAT Visual Impairment score was 29 points before surgery and 10 points at 5 months post-surgery, a change of 65%). Physical Impairment remained unchanged by surgery. Visual acuity was a poor predictor of Visual Impairment. CONCLUSIONS. The HVAT has 11 simple questions. It may be self-administered and is available on the Internet: http://www.DHAC.com. The physician may err if his decision in favor of cataract surgery is based only on visual acuity. The HVAT has the potential to guide the decision-making process between patient and physician.

What Is Outcomes Research and What Can It Tell Us

In 1989, Congress enacted PL. 101-239, establishing the Agency for Health Care Policy and Research (AHCPR). Since then, practically every specialty society has developed practice guidelines for its practitioners, and every health care organization has embarked on some outcomes research. Outcomes research has become a fashion, meaning all things to all people, and runs the risk of becoming meaningless. This article attempts to reduce the confusion by clarifying what outcomes research is and delineating its several levels, along with the methods, tools, and examples appropriate to each level. The contributions of outcomes research to health care delivery innovation to date have been modest. Ultimately, we need community health information systems, which have not only the structural and process variables but also include the outcome results, to guide decision making with regard to the health of entire communities and the appropriate investment of resources to improve health.

MANAGED CARE AND COMMUNITY-ORIENTED CARE: CONFLICT OR COMPLEMENT?

Motivated by the need for fundamental change, reform of the health care delivery system is continuing despite the recent failure of national initiatives. One aspect of this reform is the restructuring of managed care systems to include low-income, at-risk populations in their health delivery programs. It is a move that threatens current safety-net providers, which already serve these populations with programs that combine public health and traditional primary care. This paper explores this potential conflict by providing a brief history and comparison of the main features of the community-oriented primary care (COPC) and health maintenance organization (HMO) models. The authors provide a framework that contrasts the structure, process, and outcome characteristics of these two models, delineating key similarities and differences. The framework is used in profiling a service delivery system model that integrates the two systems and in discussing issues related to operationalizing the proposed integration.