RAND Corporation

About: RAND Corporation is a nonprofit organization based out in Santa Monica, California, United States. It is known for research contribution in the topics: Population & Health care. The organization has 9602 authors who have published 18570 publications receiving 744658 citations.

The Vulnerable Elders Survey: a tool for identifying vulnerable older people in the community.

Abstract: OBJECTIVES: To develop a simple method for identifying community-dwelling vulnerable older people, defined as persons age 65 and older at increased risk of death or functional decline. To assess whether self-reported diagnoses and conditions add predictive ability to a function-based survey. DESIGN: Analysis of longitudinal survey data. SETTING: A nationally representative community-based survey. PARTICIPANTS: Six thousand two hundred five Medicare beneficiaries age 65 and older. MEASUREMENTS: Bivariate and multivariate analyses of the Medicare Current Beneficiary Survey; development and comparison of scoring systems that use age, function, and self-reported diagnoses to predict future death and functional decline. RESULTS: A multivariate model using function, self-rated health, and age to predict death or functional decline was only slightly improved when self-reported diagnoses and conditions were included as predictors and was significantly better than a model using age plus self-reported diagnoses alone. These analyses provide the basis for a 13-item function-based scoring system that considers age, self-rated health, limitation in physical function, and functional disabilities. A score of ≥3 targeted 32% of this nationally representative sample as vulnerable. This targeted group had 4.2 times the risk of death or functional decline over a 2-year period compared with those with scores <3. The receiver operating characteristics curve had an area of .78. An alternative scoring system that included self-reported diagnoses did not substantially improve predictive ability when compared with a function-based scoring system. CONCLUSIONS: A function-based targeting system effectively and efficiently identifies older people at risk of functional decline and death. Self-reported diagnoses and conditions, when added to the system, do not enhance predictive ability. The function-based targeting system relies on self-report and is easily transported across care settings.

Self-Concept: The Interplay of Theory and Methods.

Abstract: : The purposes of this paper were to advance self-concept theory and to present recent methodological advances for doing so. With respect to methodology, the analyses of covariance structure, compared to simply an analysis of correlations, enabled us to test competing models and to understand the origin of the observed correlations. The conclusions that would have been drawn from the correlational data--e.g., multifaceted, hierarchical structure with increasing stability of constructs toward the apex--were modified and clarified on the basis of the analysis of covariance structure--e.g., lack of support for increasing stability. The covariance structure analytical technique also permitted us to test casual relations between latent constructs rather than between observed variables. Casual relationships among constructs, of course, cannot be tested on the basis of zero-order correlations. Clearly the covariance structure technique is a major methodological contribution to the development and testing of psychological theory in education. With respect to self-concept theory, the following conclusions seem warranted on the basis of our sample of 99 middle-class, junior high students and the literature reviewed. Self-concept is a multi-faceted construct. General self-concept can be interpreted as distinct but correlated with academic self-concept. Furthermore, subject-matter specific facets of self-concept can be interpreted as distinct, but correlated with one another and with academic and general self-concept.

Overdiagnosis Due to Prostate-Specific Antigen Screening: Lessons From U.S. Prostate Cancer Incidence Trends

Abstract: Background Overdiagnosis of clinically insignificant prostate cancer is considered a major potential drawback of prostate-specific antigen (PSA) screening. Quantitative estimates of the magnitude of this problem are, however, lacking. We estimated rates of prostate cancer overdiagnosis due to PSA testing that are consistent with the observed incidence of prostate cancer in the United States from 1988 through 1998. Overdiagnosis was defined as the detection of prostate cancer through PSA testing that otherwise would not have been diagnosed within the patient's lifetime. Methods We developed a computer simulation model of PSA testing and subsequent prostate cancer diagnosis and death from prostate cancer among a hypothetical cohort of two million men who were 60-84 years old in 1988. Given values for the expected lead time--that is, the time by which the test advanced diagnosis--and the expected incidence of prostate cancer in the absence of PSA testing, the model projected the increase in population incidence of prostate cancer associated with PSA testing. By comparing the model-projected incidence with the observed incidence derived from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registry data, we determined the lead times and corresponding overdiagnosis rates that were consistent with the observed data. Results SEER data on prostate cancer incidence from 1988 through 1998 were consistent with overdiagnosis rates of approximately 29% for whites and 44% for blacks among men with prostate cancers detected by PSA screening. Conclusions Among men with prostate cancer that would be detected only at autopsy, these rates correspond to overdiagnosis rates of, at most, 15% in whites and 37% in blacks. The observed trends in prostate cancer incidence are consistent with considerable overdiagnosis among PSA-detected cases. However, the results suggest that the majority of screen-detected cancers diagnosed between 1988 and 1998 would have presented clinically and that only a minority of cases found at autopsy would have been detected by PSA testing.

Contribution of Public Parks to Physical Activity

Abstract: Objectives. Parks provide places for people to experience nature, engage in physical activity, and relax. We studied how residents in low-income, minority communities use public, urban neighborhood parks and how parks contribute to physical activity.Methods. In 8 public parks, we used direct observation to document the number, gender, race/ethnicity, age group, and activity level of park users 4 times per day, 7 days per week. We also interviewed 713 park users and 605 area residents living within 2 miles of each park.Results. On average, over 2000 individuals were counted in each park, and about two thirds were sedentary when observed. More males than females used the parks, and males were twice as likely to be vigorously active. Interviewees identified the park as the most common place they exercised. Both park use and exercise levels of individuals were predicted by proximity of their residence to the park.Conclusions. Public parks are critical resources for physical activity in minority communities. B...

Systematic review: the evidence that publishing patient care performance data improves quality of care.

Abstract: Public reporting of health care system performance might cause patients to migrate to high-performing systems, creating a business case for quality improvement programs. The authors synthesized the...