Psychometric properties of the SCREESCO questionnaire used in a colorectal cancer screening programme-A Rasch analysis.
ABSTRACT: INTRODUCTION:Colorectal cancer (CRC) is one of the most common cancer diagnoses among both sexes. Sweden has not yet implemented any CRC screening programme, but a study, Screening of Swedish Colons (SCREESCO), is ongoing. The movement within the health care sector towards a more participatory perspective has led to the increased importance of shared decision making (SDM), and this is suggestively applied when deciding upon screening participation. There is no Swedish questionnaire for assessing the level of SDM in relation to CRC screening. Therefore, the CRC screening module of the National Survey of Medical Decisions was translated and culturally adapted into a Swedish context: the SCREESCO questionnaire. AIM:The SCREESCO questionnaire requires further evaluation, and therefore, the aim, by using the Rasch approach, was to evaluate the psychometric properties of the SCREESCO questionnaire. METHODS:A Rasch partial credit model was chosen to investigate the psychometric properties. The sample consisted of individuals invited to the SCREESCO programme, who have answered the SCREESCO questionnaire. RESULTS:Rating scale structures indicated stability for the response structure used. Satisfactory evidence for validity of internal structure was also shown for the whole questionnaire and two of three concepts/subscales, after deletion of a few items. Validity in response processes indicated acceptable, or close to acceptable, findings, while the results for unidimensionality and differential item functioning (DIF) were somewhat mixed. Separation index revealed less satisfactory results, both for the whole questionnaire and the concepts/subscales. CONCLUSION:This Rasch analysis of the SCREESCO questionnaire revealed that the questionnaire in its current form has difficulties to assess the level of SDM in relation to CRC screening. The achieved results will guide further evaluation and development with the long-term goal of having a Swedish questionnaire, to be used in the health care sector, assessing the level of SDM in relation to CRC screening.
Project description:<h4>Introduction</h4>Electronic health (eHealth) strategies are evolving making it important to have valid scales to assess eHealth and health literacy. Item response theory methods, such as the Rasch measurement model, are increasingly used for the psychometric evaluation of scales. This paper aims to examine the internal construct validity of an eHealth and health literacy scale using Rasch analysis in a population with moderate to high cardiovascular disease risk.<h4>Methods</h4>The first 397 participants of the CONNECT study completed the electronic health Literacy Scale (eHEALS) and the Health Literacy Questionnaire (HLQ). Overall Rasch model fit as well as five key psychometric properties were analysed: unidimensionality, response thresholds, targeting, differential item functioning and internal consistency.<h4>Results</h4>The eHEALS had good overall model fit (?2 = 54.8, p = 0.06), ordered response thresholds, reasonable targeting and good internal consistency (person separation index (PSI) 0.90). It did, however, appear to measure two constructs of eHealth literacy. The HLQ subscales (except subscale 5) did not fit the Rasch model (?2: 18.18-60.60, p: 0.00-0.58) and had suboptimal targeting for most subscales. Subscales 6 to 9 displayed disordered thresholds indicating participants had difficulty distinguishing between response options. All subscales did, nonetheless, demonstrate moderate to good internal consistency (PSI: 0.62-0.82).<h4>Conclusion</h4>Rasch analyses demonstrated that the eHEALS has good measures of internal construct validity although it appears to capture different aspects of eHealth literacy (e.g. using eHealth and understanding eHealth). Whilst further studies are required to confirm this finding, it may be necessary for these constructs of the eHEALS to be scored separately. The nine HLQ subscales were shown to measure a single construct of health literacy. However, participants' scores may not represent their actual level of ability, as distinction between response categories was unclear for the last four subscales. Reducing the response categories of these subscales may improve the ability of the HLQ to distinguish between different levels of health literacy.
Project description:The Coping Health Inventory for Parents (CHIP) evaluates coping patterns of parents of chronically ill children and assesses different coping strategies using three subscales. This study aimed to translate and transculturally adapt the CHIP for a Brazilian sample and investigate the preliminary psychometrics of the scale. Rating scale Rasch analysis was performed on CHIP responses, and the psychometric performance of each of the three subscales was tested. Two hundred twenty parents of individuals with health problems participated in the study, answering a sociodemographic questionnaire-the Brazilian version of the CHIP-and Folkman and Lazarus's coping questionnaire. All items exhibited good fit to the measurement model, although response categories were not used as intended and little variability on person parameter estimates was obtained. These preliminary results suggested that each construct being measured by the three subscales should be treated separately, corroborating the theoretical model of the original instrument. Suggestions to address the psychometric limitations of the instrument were made in order to improve measurement precision.
Project description:The Swallowing Quality-of-Life Questionnaire (SWAL-QoL) is considered the gold standard for assessing health-related QoL in oropharyngeal dysphagia. The Dutch translation (DSWAL-QoL) and its adjusted version (aDSWAL-QoL) have been validated using classical test theory (CTT). However, these scales have not been tested against the Rasch measurement model, which is required to establish the structural validity and objectivity of the total scale and subscale scores. Thus, the purpose of this study was to examine the psychometric properties of these scales using item analysis according to the Rasch model.Item analysis with the Rasch model was performed using RUMM2030 software with previously collected data from a validation study of 108 patients. The assessment included evaluations of overall model fit, reliability, unidimensionality, threshold ordering, individual item and person fits, differential item functioning (DIF), local item dependency (LID) and targeting.The analysis could not establish the psychometric properties of either of the scales or their subscales because they did not fit the Rasch model, and multidimensionality, disordered thresholds, DIF, and/or LID were found. The reliability and power of fit were high for the total scales (PSI?=?0.93) but low for most of the subscales (PSI?<?0.70). The targeting of persons and items was suboptimal. The main source of misfit was disordered thresholds for both the total scales and subscales. Based on the results of the analysis, adjustments to improve the scales were implemented as follows: disordered thresholds were rescaled, misfit items were removed and items were split for DIF. However, the multidimensionality and LID could not be resolved. The reliability and power of fit remained low for most of the subscales.This study represents the first analyses of the DSWAL-QoL and aDSWAL-QoL with the Rasch model. Relying on the DSWAL-QoL and aDSWAL-QoL total and subscale scores to make conclusions regarding dysphagia-related HRQoL should be treated with caution before the structural validity and objectivity of both scales have been established. A larger and well-targeted sample is recommended to derive definitive conclusions about the items and scales. Solutions for the psychometric weaknesses suggested by the model and practical implications are discussed.
Project description:Parents of a child with disability must cope with greater demands than those living with a healthy child. Coping refers to a person's cognitive or behavioral efforts to manage the demands of a stressful situation. The Coping Health Inventory for Parents (CHIP) is a well-recognized measure of coping among parents of chronically ill children and assesses different coping patterns using its three subscales. The purpose of this study was to provide further insights into the psychometric properties of the CHIP subscales in a sample of parents of children with disabilities.In this cross-sectional study, 220 parents (mean age, 33.4 years; 85% mothers) caring for a child with disability enrolled in special schools as well as in mainstream schools completed the 45-item CHIP. Rasch analysis was applied to the CHIP data and the psychometric performance of each of the three subscales was tested. Subscale revision was performed in the context of Rasch analysis statistics.Response categories were not used as intended, necessitating combining categories, thereby reducing the number from 4 to 3. The subscale - 'maintaining social support' satisfied all the Rasch model expectations. Four item misfit the Rasch model in the subscale -maintaining family integration', but their deletion resulted in a 15-item scale with items that fit the Rasch model well. The remaining subscale - 'understanding the healthcare situation' lacked adequate measurement precision (<2.0 logits).The current Rasch analyses add to the evidence of measurement properties of the CHIP and show that the two of its subscales (one original and the other revised) have good psychometric properties and work well to measure coping patterns in parents of children with disabilities. However the third subscale is limited by its inadequate measurement precision and requires more items.
Project description:The Interpersonal Needs Questionnaire (INQ) assesses Thwarted Belongingness (TB) and Perceived Burdensomeness (PB), two predictors of suicidal thoughts. Up to now, the use of item response theory (IRT) for the evaluation of the INQ has been restricted to a single study with clinically depressed and suicidal youth. Therefore, the psychometric properties of the two INQ-15-subscales TB and PB were now evaluated in a general population sample (N = 2508) and a clinical adult population sample (N = 185) using IRT, specifically the Rasch model (RM) and the graphical log-linear Rasch model (GLLRM). Of special interest was whether the INQ-subscales displayed differential item functioning (DIF) across the two different samples and how well the subscales were targeted to the two sample populations. For the clinical sample, fit to a GLLRM could be established for the PB-subscale and fit to a RM was established for a five-item version of the TB-subscale. In contrast, for the general population sample fit to a GLLRM could only be achieved for the PB-subscale. Overall, there was strong evidence of local dependence (LD) across items and of some age- and gender-related DIF. Both subscales exhibited massive DIF related to the sample, indicating that they don't work the same across the general population and clinical sample. As expected, targeting of both INQ-subscales was much better for the clinical population. Further investigations of the INQ-15 under the Rasch approach in a large clinical population are recommended to determine and optimize the scale performance.
Project description:To evaluate the psychometric properties of the Adult Strabismus-20 (AS-20)- a health-related quality of life (HRQoL) questionnaire in adults with strabismus, and if flawed, to revise the AS-20 and its subscales creating valid measurement scales.584 adults (meanage, 27.5 years) with strabismus were recruited from an outpatient clinic at a South Indian tertiary eye care centre and were administered the AS-20 questionnaire.The AS-20 was translated and back translated into two Indian languages. The AS-20 and its two 10-item subscales - 'psychosocial' and 'function'were assessed separately for fit to the Rasch model, including an assessment of the rating scale, unidimensionality (by principal components analysis), measurement precision by person separation reliability, PSR, targeting, and differential item functioning (DIF; notable > 1.0 logits).Response categories were not used as intended, thereby, required re-organization and reducing their number from 5 to 3. The AS-20 had adequate measurement precision (PSR = 0.87) but lacked unidimensionality; however, deletion of the six multi-dimensionality causing items and an additional three misfitting items resulted in 11-item unidimensional questionnaire (AS-11). Two items failed to satisfy the model expectations in the 'psychosocial' subscale and were deleted - resulting in an 8-item unidimensional scale with adequate PSR (0.81) and targeting (0.23 logits). One item misfit in the 'function' subscale and was deleted-resulting in a 9 item Rasch-revised unidimensional subscale with acceptable PSR (0.80) and targeting (0.97 logits).None of the items displayed notable DIF by age, gender and level of education.The AS-11 and its two Rasch-revised subscales - 8-item psychosocial and 9-item function subscale may be more appropriate than the original AS-20 and its two 10-item subscales for use as unidimensional measures of HRQoL in adults with strabismus in India. Further work is required to establish the validity of the revised rating scale.
Project description:BACKGROUND:To investigate the psychometric properties of the Brazilian Portuguese version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25) questionnaire in a group of patients with different eye diseases. METHODS:Cross-sectional study. All subjects completed the Portuguese version of the NEI VFQ-25 questionnaire. Another questionnaire containing a survey about clinical and demographics data was also applied. Rasch analysis was used to evaluate the psychometric properties of the NEI VFQ-25. RESULTS:The study included 104 patients with cataract, 65 with glaucoma and 83 with age macular degeneration. Mean age was 70.7 ± 9.9 years, with 143 female (56.7%) and 109 male patients (43.2%). Mean visual acuity was 0.47 and 1.17 logMAR in the better and worse eye, respectively. According to Rasch analysis, seven items were found to misfit. Those items belonged to the following subscales: general health, social function, mental health, ocular pain and role limitations. The principal component analysis of the residuals showed that 55.5% of the variance was explained by the principal component. Eight items loaded positively onto the first contrast with a correlation higher than 0.4. These items belonged to the following subscales: near vision, distance vision, mental health and dependency. After excluding those items, we were able to isolate items from the NEI VFQ-25, related only to a visual functioning component. Finally, the principal component analysis from residuals of this revised version of the NEI VFQ-25 (items related to visual function) showed that the principal component explained 61.2% of the variance, showing no evidence of multidimensionality. CONCLUSIONS:The Portuguese version of the NEI VFQ-25 is not a unidimensional instrument. We were able to find items that belong to a different trait, possible related to a socio-emotional component. Thus, in order to obtain psychometrically valid constructs, both the visual functioning and socio-emotional components should be analyzed separately.
Project description:BACKGROUND:Person-centred care is the bedrock of modern dementia services, yet the evidence-base to support its implementation is not firmly established. Research is hindered by a need for more robust measurement instruments. The 14-item Person-Centred Climate Questionnaire - Staff version (PCQ-S) is one of the most established scales and has promising measurement properties. However, its construction under classical test theory methods leaves question marks over its rigour and the need for evaluation under more modern testing procedures. METHODS:The PCQ-S was self-completed by nurses and other care staff working across nursing homes in 35 Swedish municipalities in 2013/14. A Rasch analysis was undertaken in RUMM2030 using a partial credit model suited to the Likert-type items. Three subscales of the PCQ-S were evaluated against common thresholds for overall fit to the Rasch model; ordering of category thresholds; unidimensionality; local dependency; targeting; and Differential Item Functioning. Three subscales were evaluated separately as unidimensional models and then combined as subtests into a single measure. Due to large number of respondents (n?=?4381), two random sub-samples were drawn, with a satisfactory model established in the first ('evaluation') and confirmed in the second ('validation'). Final item locations and a table converting raw scores to Rasch-transformed values were created using the full sample. RESULTS:All three subscales had disordered thresholds for some items, which were resolved by collapsing categories. The three subscales fit the assumptions of the Rasch model after the removal of two items, except for subscale 3, where there was evidence of local dependence between two items. By forming subtests, the 3 subscales were combined into a single Rasch model which had satisfactory fit statistics. The Rasch form of the instrument (PCQ-S-R) had an adequate but modest Person Separation Index (<?0.80) and some evidence of mistargeting due to a low number of 'difficult-to-endorse' items. CONCLUSIONS:The PCQ-S-R has 12 items and can be used as a unidimensional scale with interval level properties, using the nomogram presented within this paper. The scale is reliable but has some inefficiencies due to too few high-end thresholds inhibiting discrimination amongst populations who already perceive that person-centred care is very good in their environment.
Project description:BACKGROUND AND OBJECTIVE: Celiac disease (CD) is a common chronic autoimmune disorder. Both the manifestations of the disease and the burden of the compulsory life-long gluten-free diet (GFD) have been shown to be associated with impairment of health-related quality of life. The objectives of this study were to provide a cross-cultural adaptation of the specific quality of life "Celiac Disease Questionnaire" (CDQ) and to analyze its psychometric properties. MATERIALS AND METHODS: A cross-cultural French adaptation of the CDQ (F-CDQ) was obtained according to the revised international guidelines. The questionnaire was administered at baseline to 211 patients with biopsy proven CD followed-up in a single tertiary referral centre. The questionnaire was also administered after 7 days and 6 months. Reliability (intraclass correlation coefficients (ICC), Cronbach's alpha and Bland and Altman graphical analysis), validity (factorial structure and Rasch analysis, convergent validity), and responsiveness (effect size) of the F-CDQ were studied. RESULTS: The reliability of the F-CDQ was excellent with ICC and Cronbach's alpha coefficients being between 0.79 and 0.94 for the four subscales and the total score. The factorial structure and the Rasch analysis showed that the four dimensions of the original instrument were retained. Correlations with external measures (a generic measure of quality of life, an anxiety and depression instrument, a self-assessed disease severity, and clinical manifestations) were all in the expected direction confirming the validity of the instrument. Responsiveness was studied and effect sizes ? 0.20 were demonstrated for most of the subscales for patients who reported improvement or deterioration after 6 months. CONCLUSION: The F-CDQ retains the psychometric properties of the original instrument and should be useful in cross-national surveys and to assess outcome in clinical trials involving patients with CD.
Project description:BACKGROUND:Cervical cancer screening will inevitably lead to unintentional harmful effects e.g. detection of indolent pathological conditions defined as overdetection or overdiagnosis. Overdiagnosis often leads to overutilisation, overtreatment, labelling and thereby negative psychosocial consequences. There is a lack of adequate psychosocial measures when it comes to measurement of the harms of medical screening. However, the Consequences of Screening questionnaire (COS) has been found relevant and comprehensive with adequate psychometric properties in breast and lung cancer screening. Therefore, the aim of the present study was to extend the Consequences of Screening Questionnaire for use in cervical cancer screening by testing for content coverage, dimensionality, and reliability. METHODS:In interviews, the suitability, content coverage, and relevance of the COS were tested on participants in cervical screening. The results were thematically analysed to identify the key consequences of abnormal screening results. Item Response Theory and Classical Test Theory were used to analyse data. Dimensionality, invariance, and reliability were established by item analysis, examining the fit between item responses and Rasch models. RESULTS:All COS items were found relevant by the interviewees and the ten COS constructs were confirmed each to be unidimensional in the Rasch models. Ten new themes specifically relevant for participants having abnormal cervical screening result were extracted from the interviews: 'Uncertainty about the screening result', 'Uncertainty about future pregnancy', 'Change in body perception', 'Change in perception of own age', 'Guilt', 'Fear and powerlessness', 'Negative experiences from the pelvic examination', 'Negative experiences from the examination', 'Emotional reactions' and 'Sexuality' Altogether, 50 new items were generated: 10 were single items. Most of the remaining 40 items were confirmed to fit Rasch models measuring ten different constructs. However, the two items in the scale 'Change in perception of own age' both possessed differential item functioning in relation to time, which can bias longitudinal repeated measurement. CONCLUSIONS:The reliability and the dimensionality of a condition-specific measure with high content validity for women having an abnormal cervical cancer screening results have been demonstrated. This new questionnaire called Consequences Of Screening in Cervical Cancer (COS-CC) covers in two parts the psychosocial experience in cervical cancer screening.