Rewards of bridging the divide between measurement and clinical theory: demonstration of a bifactor model for the Brief Symptom Inventory.
ABSTRACT There is growing evidence that psychiatric disorders maintain hierarchical associations where general and domain-specific factors play prominent roles (see D. Watson, 2005). Standard, unidimensional measurement models can fail to capture the meaningful nuances of such complex latent variable structures. The present study examined the ability of the multidimensional item response theory bifactor model (see R. D. Gibbons & D. R. Hedeker, 1992) to improve construct validity by serving as a bridge between measurement and clinical theories. Archival data consisting of 688 outpatients' psychiatric diagnoses and item-level responses to the Brief Symptom Inventory (BSI; L. R. Derogatis, 1993) were extracted from files at a university mental health clinic. The bifactor model demonstrated superior fit for the internal structure of the BSI and improved overall diagnostic accuracy in the sample (73%) compared with unidimensional (61%) and oblique simple structure (65%) models. Consistent with clinical theory, multiple sources of item variance were drawn from individual test items. Test developers and clinical researchers are encouraged to consider model-based measurement in the assessment of psychiatric distress.
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ABSTRACT: Knowledge of coping styles is useful in clinical diagnosis and suggesting specific therapeutic interventions. However, the latent structures and relationships between different aspects of coping styles have not been fully clarified. A full information item bifactor model will be beneficial to future research. One goal of this study is identification of the best fit statistical model of coping styles. A second goal is entails extended analyses of latent relationships among different coping styles. In general, such research should offer greater understanding of the mechanisms of coping styles and provide insights into coping with stress. Coping Styles Questionnaire (CSQ) and Generalized Self-Efficacy Scale (GSES) were administrated to officers suffering from military stress. Confirmatory Factor Analyses was performed to indentify the best fit model. A hierarchical item response model (bifactor model) was adopted to analyze the data. Additionally, correlations among coping styles and self-efficacy were compared using both original and bifactor models. Results showed a bifactor model best fit the data. Item loadings on general and specific factors varied among different coping styles. All items loaded significantly on the general factor, and most items also had moderate to large loadings on specific factors. The correlation between coping styles and self-efficacy and the correlation among different coping styles changed significantly after extracting the general factor of coping stress using bifactor analysis. This was seen in changes from positive (r = 0.714, p<0.01) correlation to negative (r = -0.335, p<0.01) and also from negative (r = -0.296, p<0.01) to positive (r = 0.331, p<0.01). Our results reveal that coping styles have a bifactor structure. They also provide direct evidence of coexisting coping resources and styles. This further clarifies that dimensions of coping styles should include coping resources and specific coping styles. This finding has implications for measurement of coping mechanisms, health maintenance, and stress reduction.PLoS ONE 05/2014; 9(5):e96451. · 3.53 Impact Factor
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ABSTRACT: Background Screening and monitoring systems are increasingly used in psychotherapy, but it has been questioned whether outcome measurement using multiple questionnaires is warranted. Arguably, type and number of assessment instruments should be determined by empirical research. This study investigated the latent factor structure of a multi-dimensional outcome measurement strategy used in English services aligned to the Improving Access to Psychological Therapies (IAPT) programme. Methods Factor analyses and structural equation models were performed on 11,939 intake assessments of outpatients accessing an IAPT service between 2008 and 2010. We examined whether three routinely employed instruments (PHQ-9 for depression, GAD-7 for anxiety, WSAS for functional impairment) assess empirically different dimensions. Results The instruments were found to assess mainly one general dimension and only some items of the GAD-7 and WSAS assess unique variance beyond this general dimension. In a structural equation model the disorder-specific factor scores were predicted by patients׳ diagnostic categories. Limitations Since a large naturalistic data base was used, missing data for diagnoses and scale items were encountered. Diagnoses were obtained with brief case-finding measures rather than structured diagnostic interviews. Conclusion Although the items seem to address mostly one dimension, some variance is due to differences between individuals in anxiety and impairment. While this generally supports multi-dimensional assessment in a primary care population, the clinical upshot of the study is to concentrate attention on transdiagnostic factors as a target for treatment.Journal of Affective Disorders 09/2014; 166:270–278. · 3.71 Impact Factor
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ABSTRACT: To evaluate the effects of vascular conditions and education quality on cognition over time in White and African American (AA) older adults.The Journals of Gerontology Series B Psychological Sciences and Social Sciences 08/2014; · 3.01 Impact Factor