Item response theory evaluation of the biomedical scale of the Pain Attitudes and Beliefs Scale.

OBJECTIVES: The assessment of health care professionals' attitudes and beliefs towards musculoskeletal pain is essential because they are key determinants of their clinical practice behaviour. The Pain Attitudes and Beliefs Scale (PABS) biomedical scale evaluates the degree of health professionals' biomedical orientation towards musculoskeletal pain and was never assessed using item response theory (IRT). This study aimed at assessing the psychometric performance of the 10-item biomedical scale of the PABS scale using IRT. METHODS: Two cross-sectional samples (BeBack, n = 1016; DABS; n = 958) of health care professionals working in the UK were analysed. Mokken scale analysis (nonparametric IRT) and common factor analysis were used to assess dimensionality of the instrument. Parametric IRT was used to assess model fit, item parameters, and local reliability (measurement precision). RESULTS: Results were largely similar in the two samples and the scale was found to be unidimensional. The graded response model showed adequate fit, covering a broad range of the measured construct in terms of item difficulty. Item 3 showed some misfit but only in the DABS sample. Some items (i.e. 7, 8 and 9) displayed remarkably higher discrimination parameters than others (4, 5 and 10). The scale showed satisfactory measurement precision (reliability > 0.70) between theta values -2 and +3. DISCUSSION: The 10-item biomedical scale of the PABS displayed adequate psychometric performance in two large samples of health care professionals, and it is suggested to assess group-level professionals degree of biomedical orientation towards musculoskeletal pain

Some recommendations for developing multidimensional computerized adaptive tests for patient-reported outcomes

PURPOSE: Multidimensional item response theory and computerized adaptive testing (CAT) are increasingly used in mental health, quality of life (QoL), and patient-reported outcome measurement. Although multidimensional assessment techniques hold promises, they are more challenging in their application than unidimensional ones. The authors comment on minimal standards when developing multidimensional CATs. METHODS: Prompted by pioneering papers published in QLR, the authors reflect on existing guidance and discussions from different psychometric communities, including guidelines developed for unidimensional CATs in the PROMIS project. RESULTS: The commentary focuses on two key topics: (1) the design, evaluation, and calibration of multidimensional item banks and (2) how to study the efficiency and precision of a multidimensional item bank. The authors suggest that the development of a carefully designed and calibrated item bank encompasses a construction phase and a psychometric phase. With respect to efficiency and precision, item banks should be large enough to provide adequate precision over the full range of the latent constructs. Therefore CAT performance should be studied as a function of the latent constructs and with reference to relevant benchmarks. Solutions are also suggested for simulation studies using real data, which often result in too optimistic evaluations of an item bank's efficiency and precision. DISCUSSION: Multidimensional CAT applications are promising but complex statistical assessment tools which necessitate detailed theoretical frameworks and methodological scrutiny when testing their appropriateness for practical applications. The authors advise researchers to evaluate item banks with a broad set of methods, describe their choices in detail, and substantiate their approach for validation

Attachment styles and symptoms in individuals with psychosis

Background: The capacity to manage affects is rooted in early interactions with caregivers, which in adulthood are internalized as different attachment styles. Few studies have explored associations between all four attachment styles and symptoms. Aim: Our aim was to investigate the relations between the four attachment styles and psychological distress in a group of people with psychosis. Method: In a cross-sectional study, associations between self-reported attachment style and symptoms in a psychosis group were explored. Attachment styles were measured with the Relationship Questionnaire (RQ) and symptoms were assessed with the revised version of the Symptom Checklist (SCL-90R) Results: The analyses showed a significant positive association between preoccupied attachment and the severity of symptoms. Furthermore, the analyses indicated significant positive associations between preoccupied attachment and the subscales measuring depression, anxiety, interpersonal sensitivity, paranoia and psychoticism. We also found significant positive associations between fearful attachment and both interpersonal sensitivity and psychoticism. Conclusion: The associations between attachment styles and symptoms found here are consistent with those of previous studies. It could be important for clinicians to identify patients' attachment styles. Such knowledge would help mental health professionals to understand better the patients' capacity to handle distress and help professionals to address interventions aiming to target each patient's specific needs

Construct Validity of the Dutch Version of the 12-Item Partners in Health Scale: Measuring Patient Self-Management Behaviour and Knowledge in Patients with Chronic Obstructive Pulmonary Disease.

OBJECTIVE:The 12-item Partners in Health scale (PIH) was developed in Australia to measure self-management behaviour and knowledge in patients with chronic diseases, and has undergone several changes. Our aim was to assess the construct validity and reliability of the latest PIH version in Dutch COPD patients. METHODS:The 12 items of the PIH, scored on a self-rated 9-point Likert scale, are used to calculate total and subscale scores (knowledge; coping; recognition and management of symptoms; and adherence to treatment). We used forward-backward translation of the latest version of the Australian PIH to define a Dutch PIH (PIH(Du)). Mokken Scale Analysis and common Factor Analysis were performed on data from a Dutch COPD sample to investigate the psychometric properties of the Dutch PIH; and to determine whether the four-subscale solution previously found for the original Australian PIH could be replicated for the Dutch PIH. RESULTS:Two subscales were found for the Dutch PIH data (n = 118); 1) knowledge and coping; 2) recognition and management of symptoms, adherence to treatment. The correlation between the two Dutch subscales was 0.43. The lower-bound of the reliability of the total scale equalled 0.84. Factor analysis indicated that the first two factors explained a larger percentage of common variance (39.4% and 19.9%) than could be expected when using random data (17.5% and 15.1%). CONCLUSION:We recommend using two PIH subscale scores when assessing self-management in Dutch COPD patients. Our results did not support the four-subscale structure as previously reported for the original Australian PIH

The St George’s Respiratory Questionnaire revisited: a psychometric evaluation

Purpose The St George’s Respiratory Questionnaire (SGRQ) has clearly acquired the status of legacy questionnaire for measuring health-related quality of life in patients with chronic obstructive pulmonary disease (COPD). The main aim of this study was to assess the underlying dimensionality of the SGRQ and to investigate the added value of the empirical weights used to calculate total scores. Methods The official Dutch translation of the SGRQ was completed by 444 COPD patients participating in two clinical studies. These data were used for secondary data analysis in this study. Three complementary statistical methods were used to assess dimensionality: Mokken scale analysis (MSA), parametric multidimensional item response theory (IRT) and bifactor analysis. Additionally, the original SGRQ weighting procedure was compared to IRT-based weighting. Results The results of the MSA and multidimensional item response theory (MIRT) pointed toward a unidimensional structure. The bifactor analyses indicated that there was a strong general factor, but the group factors did have additional value. Nineteen items performed poorly in the MSA, MIRT analysis or both. Shortening the scale from 50 to 31 items did not negatively impact measurement precision. SGRQ total score and IRT-derived scores correlated strongly, 0.90 for the one-parameter model and 0.99 for the two-parameter model. Conclusion The SGRQ contains some multidimensionality, but an abbreviated version can be used as a unidimensional tool in patients with COPD. Subscale scores should be used with care. SGRQ total scores correlated highly with IRT-based scores, and thus, the weighting methods may be used interchangeably to calculate total scores