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Comparing HIV Risk Among Individuals Living in High and Low Burden Zip Codes in Atlanta, GA Using Different Risk Assessment ModelsRenfroe, Joshua 13 May 2016 (has links)
HIV risk assessment models use multiple risk factors to build composite index scores to evaluate population level HIV risk. In this report, four risk assessment models were applied to a dataset with demographic, biological, and behavioral risk factors from 927 individuals in high and low HIV burden zip code groups in metro Atlanta, GA. Predictive ability of the risk assessment models were evaluated by comparing their sensitivity and specificity, area under the ROC curve, and mean score difference between high-burden and low-burden zip code area. The results show that the proportion of study participants who scored high in the risk assessment method are significantly greater in high-HIV burden zip code area than in low-HIV burden zip code area in all four risk assessment models. The Clinical Decision Rule risk-scoring model showed the best predictive ability of HIV risk and Binary Risk Indicator model showed the best predictive ability in predicting the residence zip code area.
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Psychometric studies of the Swedish version of the Adolescent Drug Abuse Diagnosis (ADAD) instrumentBörjesson, Josefine January 2011 (has links)
This thesis describes studies into the psychometric properties of a Swedish language version of the Adolescent Drug Abuse Diagnosis (ADAD) instrument. The psychometric properties of this instrument have been examined in two previous studies: an American study was conducted by the developers of the interview, Friedman and Utada (1989), and a Swiss study was undertaken by Bolognini et al. (2001). The American and the French (as used in the Swiss study) versions of ADAD exhibit good validity and reliability, in the form of both interrater reliability and the internal consistency of the composite scores. Study I evaluated the psychometric properties of the Swedish version of the ADAD interview in normal adolescents and adolescents with antisocial problems. It was found that the instrument has good interrater reliability, that the composite scores exhibit moderate internal consistency, and that the concept validity was acceptable and similar to that of the American and Swiss versions. The results also showed that the problem areas of ADAD produced meaningful correlations. The interviewer ratings, the adolescent’s ratings and the composite scores were compared and discussed. Some problems concerning the composite scores were discovered and will need to be analyzed in future studies. Study II investigated the utility and problems associated with the composite scores in the ADAD within and between normal adolescents and adolescents with antisocial problems. When comparing interviewer severity ratings and composite scores within the two groups, the composite scores were found to behave differently to the interviewer ratings. For normal adolescents, the composite scores are generally higher than the interviewer ratings, but for the adolescents with antisocial problems the reverse is true. The interviewer severity ratings seem to be the most appropriate outcome when the objective is to separate antisocial and normal groups of adolescents from each other. The difference between the two groups is smaller as measured by composite scores. The composite scores appear to function as viable indicators of current problems in all areas except for Medical and Alcohol problem area. The critical items within the Medical and Alcohol composite scores are explored and discussed. Study III investigated the concurrent and predictive validity of the ADAD Psychological status and problem area. Concurrent validity was demonstrated by significant correlations between the ADAD, Youth Self Report (YSR) and Beck Depression Inventory (BDI) scores. The predictive validity of this problem area of the ADAD was tested by exploring its correlations with the YSR, BDI, and DICA problem ratings; moderate correlations were observed, suggesting that in clinical practice, the ADAD Psychological status and problem area may be a useful tool for the assessment and measurement of current psychological problems. The utility obtained by making decisions using the test is substantial. Overall, the results of these studies indicate that the Swedish version of ADAD appears to be a psychometrically good instrument for assessing the severity of adolescents’ problems and their need for treatment, but there are some problems with the Medical and Alcohol composite scores.
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EMPIRICAL COMPARISON OF THE STATISTICAL METHODS OF ANALYZING INTERVENTION EFFECTS AND CORRELATION ANALYSIS BETWEEN CLINICAL OUTCOMES AND SURROGATE COMPOSITE SCORES IN RANDOMIZED CONTROLLED TRIALS USING COMPETE III TRIAL DATAXu, Jian-Yi 10 1900 (has links)
<p><strong>Background:</strong> A better application of evidence-based available therapies and optimal patient care are suggested to have a positive association with patient outcomes for cardiovascular disease (CVD) patients. Electronic integration of care tested in the Computerization of Medical Practices for the Enhancement of Therapeutic Effectiveness (COMPETE) Π study showed that a shared electronic decision-support system to support the primary care of diabetes improved the process of care and some clinical markers of the quality of diabetes care. On the basis of COMPETE Π trial, COMPETE Ш study showed that older adults at increased risk of cardiovascular events, if connected with their family physicians and other providers via an electronic network sharing an intensive, individualized cardiovascular tracking, advice and support program, enhanced their process of care – using a process composite score to lower their cardiovascular risk more than those in conventional care. However, results of the effect of intervention on composite process and clinical outcomes were not similar – there was no significant effect on clinical outcomes.</p> <p><strong>Objectives:</strong> Our objectives were to investigate the robustness of the results based the commonly used statistical models using COMPETE III dataset and explore the validity of the surrogate process composite score using a correlation analysis between the clinical outcomes and process composite score.</p> <p><strong>Methods:</strong> Generalized estimating equations (GEE) were used as a primary statistical model in this study. Three patient-level statistical methods (simple linear regression, fixed-effects regression, and mixed-effects regression) and two center-level statistical approaches (center-level fixed-effects model and center-level random-effects model) were compared to reference GEE model in terms of the robustness of the results – magnitude, direction and statistical significance of the estimated effects on the change of process composite score / on-target clinical composite score. GEE was also used to investigate thecorrelation between the clinical outcomes and surrogate process composite scores.</p> <p><strong>Results:</strong> All six statistical models used in this study produced robust estimates of intervention effect. No significant association between cardiovascular events and on-target clinical composite score and individual component of on-target clinical composite score were found between the intervention group and control group. However, blood pressure, LDL cholesterol, and psychosocial index are significant predictors of cardiovascular events. Process composite score can both predict the cardiovascular events and clinical improvement, but the results were not statistically significant- possibly due to the small number of events. However, the process composite score was significantly associated with the on-target clinical composite score.</p> <p><strong>Conclusions:</strong> We concluded that all five analytic models yielded similar robust estimation of intervention effect comparing to the reference GEE model. The relatively smaller estimate effects in the center-level fixed-effects model suggest that the within-center variation should be considered in the analysis of multicenter RCTs. Process composite score may serve as a good predictor for CVD outcomes.</p> / Master of Science (MSc)
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Evaluating IRT- and CTT-based Methods of Estimating Classification Consistency and Accuracy Indices from Single AdministrationsDeng, Nina 01 September 2011 (has links)
Three decision consistency and accuracy (DC/DA) methods, the Livingston and Lewis (LL) method, LEE method, and the Hambleton and Han (HH) method, were evaluated. The purposes of the study were (1) to evaluate the accuracy and robustness of these methods, especially when their assumptions were not well satisfied, (2) to investigate the " true" DC/DA indices in various conditions, and (3) to assess the impact of choice of reliability estimate on the LL method.
Four simulation studies were conducted. Study 1 looked at various test lengths. Study 2 focused on local item dependency (LID). Study 3 checked the consequences of IRT model data misfit and Study 4 checked the impact of using different scoring metrics. Finally, a real data study was conducted where no advantages were given to any models or assumptions.
The results showed that the factors of LID and model misfit had a negative impact on " true" DA index, and made all selected methods over-estimate DA index. On the contrary, the DC estimates had minimal impacts from the above factors, although the LL method had poorer estimates in short tests and the LEE and HH methods were less robust to tests with a high level of LID.
Comparing the selected methods, the LEE and HH methods had nearly identical results across all conditions, while the HH method had more flexibility in complex scoring metrics. The LL method was found sensitive to the choice of test reliability estimate. The LL method with Cronbach's alpha consistently underestimated DC estimates while LL with stratified alpha functioned noticeably better with smaller bias and more robustness in various conditions.
Lastly it is hoped to make the software be available soon to permit the wider use of the HH method. The other methods in the study are already well supported by easy to use software
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Elementary School TVAAS Composites: A Comparison Between Title I Elementary Schools and Non-Title I Elementary Schools in TennesseePadelski, Anthony W 01 December 2016 (has links)
The goal of Title I is to provide extra instructional services and activities that support students identified as failing or most at risk of failing the state’s challenging performance standards in mathematics, reading, and writing. Low-income schools or Title I schools are the primary target of Title I funds. A school is eligible for Title I status when 40% of the school’s students are from low income families; these students are identified by their eligibility to receive free and reduced priced meals.
The purpose of this study was to determine whether there is a significant difference in elementary schools’ TVAAS Composite scores between Title I and Non-Title I schools. Specifically, this researcher examined the relationship of Title I funding with student academic growth at the elementary level. The schools were located in rural Tennessee. Data were gathered from the 2012-2013 and 2013-2014 Tennessee State Report Cards and the TNDOE to determine if there was a statistically significant difference between the 2 types of schools. Research indicated mixed reviews on the impact Title I funds have on lower socioeconomic schools.
The researcher performed 5 paired t test and 8 Pearson correlation coefficients. There was a significant difference in the schools’ composite scores between Title I and Non-Title I elementary schools in Tennessee. Non-Title I elementary schools in Tennessee had higher composite scores than those of the Title I elementary schools. Results from the Pearson correlations indicated no significant relationships for mean years of teaching experience with school composite scores.
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