Factor structure of the SOC scale 13-item version in Japanese university students

The purpose of the present study was to examine the construct validity of Antonovsky's (1987) sense of coherence scale (SOC) 13-item version, with a sample of Japanese university students. Subjects were 1,110 university students who completed a self-administered questionnaire including items on individual characteristics (age, sex), the Zung self-rating depression scale (SDS) and the SOC scale. Exploratory factor analysis of the SOC scale yielded an interpretable two-factor solution with "comprehensibility-manageability" and "meaningfulness". Confirmatory factor analysis demonstrated an a priori defined SOC second-order factor model composed of comprehensibility-manageability and meaningfulness factor to have an acceptable fit (chi-square=327.065, df=64, GFI=0.957, CFI=0.872, RMSEA= 0.061). Moreover, structural equation modeling showed that there are theoretically consistent relationships among individual SOC factors and depression. In particular, the meaningfulness factor proved better predictor of depression than the comprehensibility-manageability factor. These findings support the construct validity of the SOC scale and suggest that two SOC sub scores may provide clinically applicable information, rather than the total score.     

Psychometric evaluation of the WHOQOL-BREF in community-dwelling older people in Taiwan using Rasch analysis

Objective  To examine the psychometric characteristics of the brief version of the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire in rural-community-dwelling older people in Taiwan using Rasch analysis. Methods  This is a cross-sectional study. A total of 1200 subjects aged ≥65 years were recruited to complete the 26-item WHOQOL-BREF. Scale dimensionality, item difficulty, scale reliability and separation, item targeting, item-person map, and differential item functioning (DIF) were examined. Results  The four WHOQOL-BREF scales (physical capacity, psychological well-being, social relationships, and environment) were found to be unidimensional and reliable. The item–person map for each domain indicated that the spread of the item thresholds sufficiently covered the latent trait continuum being measured. However, gaps in content coverage were identified in the social domain. Analyses of the DIF revealed that one psychological item (body image) exhibited DIF across the two age groups (old–old vs. young–old) and that two social items (sexual activity and friends’ support) displayed DIF across genders and the two age groups. Conclusions  Rasch analysis is a comprehensive method of psychometric evaluation of the WHOQOL-BREF and identifies areas for improvements. Three items displaying age-related DIF (body image, sexual activity, and friends’ support) may potentially cause biased health-related QOL assessments, and their impacts on scores should be carefully examined.     

Measuring stigma across neurological conditions: the development of the stigma scale for chronic illness (SSCI)

Purpose  Most measures of stigma are illness specific and do not allow for comparisons across conditions. As part of a study of health-related quality of life for people with neurological disorders, our team developed an instrument to assess the stigma for people with chronic illnesses. Methods  We based item content on literature review, responses from focus groups, and cognitive interviews. We then administered the items to people with neurological disorders for psychometric testing. Results  Five hundred eleven participants completed items of the stigma scale. Exploratory factor analysis produced two factors that were highly correlated (r = 0.81). Confirmatory factor analysis produced high standardized loadings on an overall stigma factor (0.68–0.94), with poorer loadings on the two sub-domains (−0.12 to 0.53). These results demonstrated a sufficiently unidimensional scale that corresponded with the bifactor model. Item response theory modeling suggested good model fit, and differential item functioning analyses indicated that the 24-item scale showed potential for measurement equivalence across conditions. Conclusions  Our efforts produced a stigma scale that had promising psychometric properties. Further study can provide additional information about the SSCI and its benefit in measuring the impact of stigma across conditions.     

The 6-item CTS symptoms scale: a brief outcomes measure for carpal tunnel syndrome

Objective  To develop a psychometrically appropriate brief symptoms measure of carpal tunnel syndrome (CTS). Methods  Preoperative CTS 11-item symptom severity and 8-item functional status scales from 693 patients (71% women) with CTS were subjected to exploratory factor analysis and item response theory (IRT) analysis yielding a revised CTS symptoms scale. A validation sample of 213 patients (68% women) with CTS completed the 11-item disabilities of the arm, shoulder and hand (QuickDASH), and the revised symptoms scale and 116 patients also completed the original CTS symptom severity scale (median interval 11 days). Results  Of the 11 CTS symptom severity scale items, 2 items that on factor analysis associated with the functional status items were removed. After IRT recalibrations of the remaining symptom severity scale items, 2 non-fitting items were removed and 2 items were merged creating the 6-item CTS symptoms scale. Factor analysis showed one dominant factor explaining 58% of the variance. Reliability was high (Cronbach alpha = 0.86; IRT person separation reliability = 0.88). No item displayed significant differential item functioning. The 6-item CTS symptoms scale showed strong correlation with the QuickDASH (r = 0.70) and agreement with the original symptom severity scale (ICC = 0.80). Conclusion  The 6-item CTS symptoms scale has good reliability and validity and can be used to measure symptom severity and treatment outcome in CTS.     

Unidimensional 12-Item Zarit Caregiver Burden Interview for the Assessment of Dementia Caregivers’ Burden Obtained by Item Response Theory

ObjectivesTo develop a one-dimensional version of the 22-item Zarit Caregiver Burden Interview (ZBI) by applying item response theory approaches.MethodsThe answers to the 22-item ZBI of 241 caregivers participating in a clinical trial were analyzed 1) with a Mokken nonparametric item response theory analysis to ascertain the dimensional structure underlying the scale and obtain a one-dimensional reduced version, 2) with the Samejima’s graded response model to assess the item characteristics of the reduced version, and 3) with confirmatory factor analysis to confirm the unidimensionality of the reduced ZBI version and assess the item loadings to the burden latent variable.ResultsMokken analysis resulted in a major one-dimensional scale comprising 12 items directly related with burden. All items showed scalability indices over 0.30. The scalability for the overall scale was 0.44 defining a medium scale according to Mokken’s criteria. An unconstrained Samejima’s graded response model showed appropriate fit, and most items of the reduced 12-item ZBI presented pertinent difficulty and discrimination parameters. The results of the 12-item ZBI confirmatory factor analysis fitted to a one-dimensional latent structure for burden (comparative fit index=0.975; root-mean-square error of approximation=0.067; weighted root mean square residual=0.677). All factor lodgings were above 0.40 with items 9 (strained by the relative) and 22 (overall feeling of burden) presenting the highest loadings.ConclusionsThe reduced 12-item ZBI fits a one-dimensional latent variable of burden. Further psychometric studies, focusing on its equivalence for different populations, sensitivity to change, and minimal important difference are warranted.     

Validating, Improving Reliability, and Estimating Correlation of the Four Subscales in the WHOQOL-BREF using Multidimensional Rasch Analysis

Objective: This study examined the construct validity, and improved the test reliability and the estimation accuracy for the correlation between domains of the WHOQOL-BREF using multidimensional Rasch analysis. Method: A total of 13,083 adults were administered the 28-item WHOQOL-BREF Taiwan version, which consists of 4 subscales (domains). The multidimensional form of the partial credit model was used to examine the fit of the 4 subscales. For comparison, each subscale individually was also fitted to the unidimensional partial credit model. Standard item fit statistics and analysis of differential item functioning (DIF) were used to check model-data fit. Results: After excluding 2 overall items and deleting 7 DIF items, the remaining items of each subscale in the WHOQOL-BREF constituted a single construct. The test reliabilities and correlations between domains obtained from the multidimensional approach, (0.82–0.86) and (0.79–0.89), respectively, were much higher than those obtained from the unidimensional approach, (0.67–0.75) and (0.53–0.65), respectively. Conclusion: The 19-item WHOQOL-BREF measures more succinct latent traits than the original design. The multidimensional approach yields not only more accurate estimates for the correlation between domains but also substantially higher reliabilities, than the standard unidimensional approach.     

A simplified way of measuring sense of coherence: Experiences from a population survey in Sweden

Antonovsky's concept sense of coherence (SOC) has gained muchattention during the last few years as an important factor inthe understanding of social factors behind health and illness.The questionnaire developed to measure SOC may, however, forpractical reasons be difficult to use. In a recently conductedpopulation survey in Sweden, we were faced with the problemof incorporating the ideas behind SOC without being able toinclude the 29-item instrument. Instead, 3 questions were constructedin order to capture each of the 3 dimensions included in SOC,namely manageability, meaningfulness and comprehensibillity.In this research note we present our simplified version of SOCand the properties of the measure obtained. We conclude thatthe simplified measure we have suggested might be a useful substitutefor the original scale, especially In cases where informationon SOC would otherwise have been totally omitted.     

Sense of coherence among Bedouin women in polygamous marriages compared to women in monogamous marriages

ABSTRACT

We compared sense of coherence (SOC) among Bedouin women in polygamous with those in monogamous marriages. SOC is a global orientation toward life as comprehensible, manageable, and meaningful, and is derived from generalized resistance resources that promote effective coping in stressful life situations. Strong SOC may be a resource for strengthening resilience and promoting health. We administered questionnaires to 464 Indigenous Arab Bedouin women (ages 18–49 years) in 2008–2009 using the 13-item SOC questionnaire. Contrary to our hypothesis, SOC was higher among women in polygamous compared to monogamous marriages. Husband‘s education, husband’s abandonment of the household, living in unrecognized villages, and low mastery (perception of one’s ability to control life situations) were associated with higher SOC. These results might suggest that polygamy may provoke new coping mechanisms among women as they reappraise life amidst low mastery, accept cultural norms, and marshal new resources, thereby increasing key elements of SOC, including comprehensibility, manageability, and meaningfulness. Interventions and services seeking to empower women in polygamous marriages should build on their resilience.     

Development of the Person-Centered Contraceptive Counseling scale (PCCC), a short form of the Interpersonal Quality of Family Planning care scale

ObjectivePerson-centeredness is a critical component of quality in family planning. We previously validated an 11-item Interpersonal Quality of Family Planning (IQFP) scale. We sought to create a parsimonious version of the scale in preparation for testing its appropriateness as a patient-reported outcome performance measure.Study designTo explore clarity and importance of each of the 11 items, we conducted English and Spanish cognitive interviews with patients who received contraceptive counseling (n = 33) at 3 publicly funded California clinics. We triangulated these results with psychometric analysis of previously collected IQFP data (n = 1097) to assess validity and reliability of selected item combinations.ResultsThe 11-item IQFP scale was reduced to a 4-item scale (the Person-Centered Contraceptive Counseling scale, or PCCC) that includes items evaluating provider performance regarding respect for patients, information provision, and eliciting and honoring patient preferences for birth control. Interview participants deemed the items included in the 4-item PCCC important and clear in both English and Spanish versions of the instrument. The 4-item PCCC retained the 11-item IQFP's psychometric properties, including internal consistency (Cronbach's alpha = 0.92 vs 0.97 for the PCCC and IQFP, respectively) and a consistent single factor analysis solution (factor loadings = 0.86–0.92 and 0.81–0.91). The 4-item PCCC additionally retained the construct and predictive validity of the IQFP.ConclusionsThe 4-item PCCC is a valid and reliable as a measure of person-centered contraceptive counseling that reflects patients’ perspectives on contraceptive counseling.ImplicationsPerson-centered measures such as the 4-item PCCC can help inform efforts to improve health care quality. Future work will investigate the validity and reliability of the 4-item PCCC as a performance measure to determine the appropriateness of its use in the quality improvement context.     

Evaluation of change in dietitians’ perceived comprehensibility and difficulty of the Patient‐Generated Subjective Global Assessment (PG‐SGA) after a single training in the use of the instrument

Background

The Patient‐Generated Subjective Global Assessment (PG‐SGA) is an instrument used to assess malnutrition and its risk factors. Some items of the PG‐SGA may be perceived as hard to comprehend or as difficult by healthcare professionals. The present study aimed to determine whether and how dietitians’ perceptions of comprehensibility and difficulty of the PG‐SGA change after a single training in PG‐SGA use.

Methods

In this prospective evaluation study, Dutch PG‐SGA‐naïve dietitians completed a questionnaire regarding perceived comprehensibility and difficulty of the PG‐SGA before (T0) and after (T1) receiving a single training in the use of the instrument. Perceived comprehensibility and difficulty were operationalised by calculating item and scale indices for comprehensibility (I‐CI, S‐CI) and difficulty (I‐DI, S‐DI) at T0 and T1. An item index of 0.78 was considered acceptable, a scale index of 0.80 was considered acceptable and a scale index of 0.90 was considered excellent.

Results

A total of 35 participants completed the questionnaire both at T0 and T1. All item indices related to comprehensibility and difficulty improved, although I‐DI for the items regarding food intake and physical examination remained below 0.78. Scale indices for difficulty and comprehensibility of the PG‐SGA changed significantly (P < 0.001) from not acceptable at T0 (S‐CI = 0.69; S‐DI = 0.57) to excellent for comprehensibility (S‐CI = 0.95) and acceptable for difficulty (S‐DI = 0.86) at T1.

Conclusions

The findings of the present study suggest that significant improvement in PG‐SGA‐naïve dietitians’ perception of comprehensibility and difficulty of the PG‐SGA can be achieved quickly by providing a 1 day of training in the use of the PG‐SGA.     

Psychometric evaluation and predictive validity of Ryff's psychological well-being items in a UK birth cohort sample of women

Background

Investigations of the structure of psychological well-being items are useful for advancing knowledge of what dimensions define psychological well-being in practice. Ryff has proposed a multidimensional model of psychological well-being and her questionnaire items are widely used but their latent structure and factorial validity remains contentious.

Methods

We applied latent variable models for factor analysis of ordinal/categorical data to a 42-item version of Ryff's psychological well-being scales administered to women aged 52 in a UK birth cohort study (n = 1,179). Construct (predictive) validity was examined against a measure of mental health recorded one year later.

Results

Inter-factor correlations among four of the first-order psychological well-being constructs were sufficiently high (> 0.80) to warrant a parsimonious representation as a second-order general well-being dimension. Method factors for questions reflecting positive and negative item content, orthogonal to the construct factors and assumed independent of each other, improved model fit by removing nuisance variance. Predictive validity correlations between psychological well-being and a multidimensional measure of psychological distress were dominated by the contribution of environmental mastery, in keeping with earlier findings from cross-sectional studies that have correlated well-being and severity of depression.

Conclusion

Our preferred model included a single second-order factor, loaded by four of the six first-order factors, two method factors, and two more distinct first-order factors. Psychological well-being is negatively associated with dimensions of mental health. Further investigation of precision of measurement across the health continuum is required.     

Adapting “The Staff Attitudes to Nutritional Nursing Care scale” to geriatric nursing care

Objective  A positive attitude is assumed to be important in nursing staff’s help and support of elderly people during meals. As there is no specific tool for measuring staff’s attitudes regarding important issues within eating and nutrition, the SANN (Staff Attitudes to Nutritional Nursing Care) scale was developed. The scale was developed and tested in nursing staff working at resident homes, and the number of items was reduced from 63 to 19 with five underlying factors. The aim of this study was to describe how the SANN scale was adapted and tested in nursing staff working in different types of elderly care. Design: The raw 63-item version went through minor changes, and one unclear worded item was excluded. The changed raw 62-item version was answered by 188 nursing staff working at six hospital care clinics and 64 staff working at one resident home. Results  The analysis reduced the 62 items to 18, and the adapted scale was named the SANN-G scale, G standing for “geriatric care”. A rotated factor analysis gave a five-factor solution, explaining 54% of the variance. The scale achieved good internal reliability, with a Cronbach’s alpha of 0.83. Fourteen items fulfilled inclusion criteria in both the SANN and the SANN-G scales. Conclusion  The SANN-G scale is practicable for use in staff working in different types of elderly care. It can be used to explore existing attitudes and identify areas with a low degree of prevailing positive attitudes as well as to evaluate whether and how attitudes change after nutritional education and intervention.     

Rasch analysis of the short form 8-item Parkinson’s Disease Questionnaire (PDQ-8)

Purpose To evaluate the Italian version of the 8-item Parkinson’s Disease Questionnaire (PDQ-8)—a subset of PDQ-39 (a 39-item health-related quality of life instrument for subjects with Parkinson’s Disease [PD])—through classical psychometric techniques and Rasch analysis. Methods Two convenience samples (100 PD subjects each) were observed consecutively from 2004 to 2006. One group completed the PDQ-8 nested within PDQ-39, the other, the stand-alone PDQ-8. Results Once verified that the two independent samples came from the same population and showed consistent item calibrations using differential item functioning analysis, the two groups were combined. Cronbach’s alpha was 0.72. According to Rasch analysis, the response scale of PDQ-8 could be simplified into a 3-category rating scale. After that, all the PDQ-8 items fitted the construct that the scale was intended to measure. Item separation reliability of PDQ-8 was 0.98 and person separation reliability was 0.70. Principal component analysis on the standardized residuals suggested a minor departure in the data from Rasch criteria (multidimensionality) and some marginal inter-item dependency. Conclusions The PDQ-8 embedded in the PDQ-39 presented psychometric properties similar to the stand-alone PDQ-8. Our results, while consistent with previous classical psychometric analyses, add information on the meaningfulness of PDQ-8 in people with PD. In particular, a simplification of its rating scale is recommended. Moreover, additional analyses should be performed in order to further check unidimensionality and local dependence, and try to improve item selection and scaling properties of the questionnaire. In order to use the PDQ-8 for clinical decision-making in reference to individuals, its reliability should first be increased.     

Die Universität – ein kohärentes Setting?

Background

This study examined the sense of coherence (SOC) of students, especially for those in the university setting, as well as their perceived quality of life.

Methods

A questionnaire that assesses SOC of university staff was adapted for students; 191 students at an Austrian university answered these items and questions regarding their quality of life.

Results

Confirmatory factor analysis supported the three-dimensionality of the“Students’ SoC” scale, which showed significant effects regarding the students’ quality of life.

Conclusion

The manageability and meaningfulness of university events is associated with respondents’ well-being. Health promotion should implement interventions that ensure well-defined structures and more codetermination and participation for students.     

Structural validity and temporal stability of the 13-item sense of coherence scale: Prospective evidence from the population-based HeSSup study

Study objective: To investigate whether the structure of Antonovsky’s [Unraveling the Mystery of Health. How People Manage Stress and Stay Well. San Francisco: Jossey-Bass, 1987] 13-item Sense of Coherence (SOC) scale remains invariant across time and across age groups and whether any differences in stability of and mean changes in SOC can be seen between young people and individuals aged 30 or above. Design: Prospective study with a population-based sample of 18,525 Finns of whom 4,682 were under age 30 and 13,843 over age 30 at both the baseline and 5-year follow-up surveys (the HeSSup study). Results: Confirmatory factor analysis supported the correlated 3-factor solution for the SOC scale and its equivalent second-order factor structure at both measurement times and in both age groups. According to Structural Equation Modelling (SEM), SOC was more stable among subjects over 30 years (stability coefficient 0.81) than among younger adults (0.70). The mean level of SOC was higher among subjects over age 30 than subjects under age 30 at both times. The level of SOC increased during the follow-up period in both age groups but to a greater extent among the younger than older age group. Conclusions: These data suggest relatively high structural validity and high stability for the 13-item SOC measure and support the notion that SOC becomes more stable following maturation. The 13-item SOC measure seems to provide a psychometrically sound survey instrument for testing Antonovsky’s theory on life orientation and health.     

Measuring global physical health in children with cerebral palsy: illustration of a multidimensional bi-factor model and computerized adaptive testing

Purpose  The purposes of this study were to apply a bi-factor model for the determination of test dimensionality and a multidimensional CAT using computer simulations of real data for the assessment of a new global physical health measure for children with cerebral palsy (CP). Methods  Parent respondents of 306 children with cerebral palsy were recruited from four pediatric rehabilitation hospitals and outpatient clinics. We compared confirmatory factor analysis results across four models: (1) one-factor unidimensional; (2) two-factor multidimensional (MIRT); (3) bi-factor MIRT with fixed slopes; and (4) bi-factor MIRT with varied slopes. We tested whether the general and content (fatigue and pain) person score estimates could discriminate across severity and types of CP, and whether score estimates from a simulated CAT were similar to estimates based on the total item bank, and whether they correlated as expected with external measures. Results  Confirmatory factor analysis suggested separate pain and fatigue sub-factors; all 37 items were retained in the analyses. From the bi-factor MIRT model with fixed slopes, the full item bank scores discriminated across levels of severity and types of CP, and compared favorably to external instruments. CAT scores based on 10- and 15-item versions accurately captured the global physical health scores. Conclusions  The bi-factor MIRT CAT application, especially the 10- and 15-item versions, yielded accurate global physical health scores that discriminated across known severity groups and types of CP, and correlated as expected with concurrent measures. The CATs have potential for collecting complex data on the physical health of children with CP in an efficient manner.     

Design of a questionnaire for evaluating the quality of life of postpartum women (PQOL) in China

Objective  To design an instrument for measuring quality of life (QOL) of postpartum women in China 0–12 months after delivery. Methods  A standardized procedure included the following activities: (1) item pool development by in-depth interview and focus group discussion with postpartum women, consultation with experts, participant observation, and literature review; (2) item pool modification by experts and postpartum women; (3) item selection used multiple methods including expert scoring, factor analysis, coefficient of variation, item-removed Cronbach's alpha, item-expected domain correlation, item-unexpected domain correlation and test–retest correlation analysis, based on the data of item pool test among women at 0–12 months after childbirth and maternal health experts. Results  More than 167 items were generated, of which 101 were considered suitable for the questionnaire pool. Ten experts and 15 women then revised them. The 101-revised-item pool was tested on 200 women and ten experts scored the importance of each item. Based on these data, 40 items referring to child care, physical function, psychological function, and social support were selected for the final questionnaire. Conclusions  This was the first questionnaire for evaluating postpartum QOL of women in China. We need to do additional fieldwork to further establish its validity and reliability.     

Validez y confiabilidad de la escala de sentido de coherencia en estudiantes de grado de enfermería de una universidad española

ObjectiveTo analyze the factor structure of the OLQ-13 scale and to study the direct relationship between sense of coherence and lifestyles in university students of nursing.MethodCross-sectional study. Location: University of Jaén. Andalusia, Spain. Participants: 384 students from the first three years of the nursing degree in the University of Jaén. Main measurement: Internal consistency was studied by Cronbach's alpha, reliability test-retest was measured by intraclass coefficient correlation (ICC) and construct validity was analysed by exploratory factor analysis, confirmatory factor analysis and known-groups technique.ResultsThe internal consistency of the scale was adequate (Cronbach α = 0.809). The ICC for the reliability test-retest was 0.91. The exploratory factor analysis showed 3 factors explaining 50.13% of the variance. The confirmatory factor analysis showed f goodness-of-fit indexes for the proposed model CFI = 0.965; RMSA = 0.041; GFI = 0.963; SRMR = 0.041. Statistically significant differences in sense of coherence were found among the subgroups of students with healthy and unhealthy lifestyles (p < 0.001).ConclusionsThe study confirms the multidimensionality of the OLQ-13 scale, in which 3 factors were identified: external meaningful, comprehensibility and manageability, and internal comprehensibility and manageability. The OLQ-13 may be a valid and reliable scale for use in the Spanish university population.     

A patient-based questionnaire to assess outcomes of foot surgery: Validation in the context of surgery for hallux valgus

Background: A patient-based outcome measure with good measurement properties is urgently needed for use in clinical trials of foot surgery. Methods: We evaluated an existing foot pain and disability questionnaire (the Manchester Foot Pain and Disability Questionnaire) for its suitability as an outcome measure in the context of hallux valgus corrective surgery. Interviews with patients led to initial changes, resulting in 20 candidate questionnaire items with five response categories each. These were tested in a prospective study of 100 patients (representing 138 foot operations) undergoing hallux valgus corrective surgery. Analysis of underlying factor structure, dimensionality, internal reliability, construct validity and responsiveness of the questionnaire items in relation to (i) SF-36 general health survey and (ii) American Orthopaedic Foot & Ankle Society (AOFAS) hallux clinical scale resulted in a final 16 item questionnaire (the ‘Manchester-Oxford Foot Questionnaire’ (MOXFQ)), consisting of three domains/scales: ‘Walking/standing’ (seven items), ‘Pain’ (five items) and ‘Social interaction’ (four items) each having good measurement properties. All three domains were unidimensional. Conclusions: The new 16-item MOXFQ has good measurement properties in the context of outcomes assessment of surgery for hallux valgus. Future studies should assess the MOXFQ in the context of surgery for other foot and ankle conditions.