Graphical Loglinear Rasch Models Research Articles

Perceived Stress and Perceived Lack of Control of Student Teachers in Field Practice Placements in Schools during the COVID-19 Pandemic: Validity of the PSS-10 Adapted to the Field Practice Context

Field practice placements contribute substantially to students’ gradual attainment and final mastery of the skills of the teaching profession. The aim of this study was to adapt the Danish consensus translation of the PSS-10 to assess perceived stress during field practice placements of varying durations and to investigate its validity for use with student teachers in field practice during the COVID-19 pandemic. Data were collected upon completion of 6 weeks of a field placement at one of three levels (N = 359), and grades from the field practice exam were obtained. To resolve any issues with differential item functioning and lack of item independence, graphical loglinear Rasch models were used. Criterion validity was investigated in relation to the level of field practice and subsequent grades. The results showed that items 10 and 4 had to be eliminated; both subscales had locally dependent items, and one item in the perceived lack of control subscale functioned differentially relative to the level of field practice placement. Criteria expectations were confirmed, though not all were significant. The psychometric properties of the adapted PSS-10 were in line with previous findings on the original PSS-10 subscales. Score levels can be used as benchmarks in post-COVID-19 studies of student teachers’ field-practice-related perceived stress.

Measuring child and adolescent well-being in Denmark: Validation and norming of the Danish KIDSCREEN-10 child/adolescent version in a national representative sample of school pupils in grades five through eight.

KIDSCREEN-10 is a generic instrument for measuring global health-related quality of life among 8-18-year-old children and adolescents. This study examines the criterion-related construct validity and psychometric properties of the Danish language version of the KIDSCREEN-10 using Rasch models. A further aim was to construct Danish norms based on the resulting person parameter estimates from the Rasch models. Data consists of a nationally representative cross-sectional survey of 8171 children in the 5th to 8th grade of primary school in Denmark. No adequate fit to the Rasch model or a graphical loglinear Rasch model could be established for the KIDSCREEN-10 in the full sample of children (n = 8171). Results based on analyses with increasing samples sizes showed that even with the smallest sample item 3 (Kid3) of the KIDSCREEN-10 did not fit the Rasch model. After elimination of Kid3, substantial local dependence and differential item functioning relative to gender and grade level was still present. Already with a sample size of 630 fit to the Rasch model or a graphical loglinear Rasch model adjusting for local dependence and differential item functioning was not established. Therefore, generation of Danish norms was not realizable, as this requires valid sum scores and estimates of the person parameters for an adequate number of cases. Thus, the Danish language version of the child/adolescent self-report KIDSCREEN-10 questionnaire cannot be recommended for use in population-level studies. Neither can use in small sample be recommended as adjustment for differential item functioning and local dependence is ambiguous.

Cross-cultural validity and psychometric properties of the International Trauma Questionnaire in a clinical refugee sample

ABSTRACT Background: The ICD-11 post-traumatic stress disorder (PTSD) and complex PTSD diagnoses have been examined in several studies using the International Trauma Questionnaire (ITQ). The cross-cultural validity of the ITQ has not previously been studied using item responses theory methods focused on the issue of equal item functioning and thus comparability of scores across language groups. Objective: To investigate the cross-cultural validity of the ITQ scales considering specifically local independence of items and differential item functioning (DIF) in a cross-cultural sample of refugees. Method: Data from 490 treatment-seeking refugees were included, covering Danish, Arabic, and Bosnian languages and different levels of interpreter-assisted administration. Rasch and graphical log-linear Rasch models were used. Results: There was strong local dependence among items from the same symptom clusters in the PTSD and disorders in self-organization (DSO) scales, except between affective dysregulation items. Weak local dependence was discovered between an item from the affective dysregulation cluster and an item from the disturbed relationship cluster. There was no evidence of DIF related to language or interpreter assistance. There was evidence of DIF for two PTSD items relative to gender and time since the traumatic event. The targeting of the scales to the study population was not optimal. Reliability varied from 0.55 to 0.78 for subgroups. Conclusions: The PTSD and the DSO scales have stable psychometric properties across the Danish, Arabic, and Bosnian language versions and different levels of assisted administration. Scores are comparable across these groups. However, DIF relative to gender and time since trauma introduces considerable measurement bias. DIF-adjusted summed scale scores or estimated person parameters should be used to avoid measurement bias. Future research should investigate whether scales including more and/or alternative items that require higher levels of PTSD and DSO to be endorsed will improve targeting and measurement precision for refugee populations.

Critical thinking of psychology students: A within- and cross-cultural study using Rasch models.

The primary aim of this study was to conduct a cross-cultural comparison of the level of critical thinking of Danish and Spanish psychology students (N=788) attending innately different bachelor-level courses; personality psychology and introductory statistics/research methods. Several instruments are available for the assessment of critical thinking (CTh), but most are, however, unsuitable for use in large surveys with many constructs, due to length or single-person administration formats. One brief and much-used scale is the CTh scale in the Motivated Strategies for Learning Questionnaire (MSLQ), used in this study. To ensure unbiased comparisons across countries and courses, our secondary aim was to investigate the content validity, as well as the psychometric properties, of the CTh scale to ensure the most accurate and unbiased comparison. For this purpose, Rasch and graphical loglinear Rasch models were used. After reducing the number of items due to content validity issues, the CTh scale fitted Rasch models within each national sample, and was measurement invariant relative to age group, gender, course and university. In the cross-cultural item analysis, two items functioned differentially relative to nationality, and the scale fitted a graphical loglinear Rasch model. CTh scores related to introductory statistics/research methods courses differed significantly from scores related to personality psychology, for Danish students only.

Classification of loneliness using the T-ILS: Is it as simple as it seems?

Student well-being is a growing issue in higher education, and assessment of the prevalence of conditions as loneliness is therefore important. In higher education and population surveys the Three-Item Loneliness Scale (T-ILS) is used increasingly. The T-ILS is attractive for large multi-subject surveys, as it consists of only three items (derived from the UCLA Loneliness Scale). Several ways of classifying persons as lonely based on T-ILS scores exist: dichotomous and trichotomous classification schemes and use of sum scores with rising levels indicating more loneliness. The question remains whether T-ILS scores are comparable across the different population groups where they are used or across groups of students in the higher education system. The aim was to investigate whether the T-ILS suffers from differential item functioning (DIF) that might change the loneliness classification among higher education students, using a large sample just admitted to 22 different academy profession degree programs in Denmark (N=3,757). DIF was tested relative to degree program, age groups and gender. The framework of graphical loglinear Rasch models was applied, as this allows for adjustment of sum scores for uniform DIF, and thus for assessment of whether DIF might change the classification. Two items showed DIF relative to degree program and gender, and adjusting for this DIF changed the classification for some subgroups. The consequences were negligible when using a dichotomous classification and larger when using a trichotomous classification. Therefore, trichotomous classification should be used with caution unless suitable adjustments for DIF are done prior to classification.

Item analysis of the KIDSCREEN-10 using Rasch modelling

AimTo test the psychometric properties of the KIDSCREEN-10.BackgroundIt is important to assess mental health and well-being in children for an early detection of psychological problems or hidden morbidities. There is limited knowledge about the psychometric quality of the reduced version of the KIDSCREEN questionnaire with only 10 items.MethodsAnalysis of psychometric properties was done by fitting Rasch models and graphical loglinear Rasch models to data collected in a study on acculturation of primary school children and their teachers in 2017.ResultsThe data did not fit a Rasch model but did fit a graphical loglinear Rasch model. There was local dependence for four item pairs and differential item functioning for gender and citizenship.ConclusionsThe KIDSCREEN-10 provides essentially valid measurements of health-related quality of life in children if local dependency and dif ferential item functioning are taken into account. Reliability and targeting were less than satisfactory, especially for certain subgroups but reliability was adequate for most groups.

Sense of personal control: Can it be assessed culturally unbiased across Aboriginal and non-Aboriginal Australians?

In recent decades, several studies have emphasized sense of personal control as a prominent aspect of Aboriginal health. However, one limitation is that instruments available to measure personal control were originally developed in western countries and validation for Aboriginal Australians has not been conducted. The aims of the current study were to evaluate whether the Sense of Personal Control Scale (SPCS) can be used to obtain culturally unbiased measurement of personal control across Aboriginal and non-Aboriginal Australians and to assess the psychometric properties of the SPCS for Aboriginal and non-Aboriginal Australian. Methods: The current study utilized two Australian subsamples retrieved from the Teeth Talk Study (n = 317) and the National Survey of Adult Oral Health 2004–2006 (n = 3,857) in which the SPCS was included. Graphical Loglinear Rasch Models (GLLRM) were used to fulfill the aims of the study. Results: The Perceived Constraints subscale fitted a GLLRM for Aboriginal Australians after the exclusion of three items, while fit to any Rasch model (RM) or GLLRM model could not be found in the non-Aboriginal sample. The Mastery subscale fitted a GLLRM in the non-Aboriginal sample after the exclusion of one item. In the Aboriginal sample, two items of the Mastery subscale fitted the RM, however, two items cannot be considered as a scale. Conclusion: In the present study, we showed that the development of new items is crucial before the revised SPCS might constitute a valid and reliable measure of sense of personal control in both Aboriginal and non-Aboriginal Australian populations, and it is possible to assess whether the SPCS can be measured without bias across these two populations.

The Parental Stress Scale revisited: Rasch-based construct validity for Danish parents of children 2\u201318\u2009years old with and without behavioral problems

BackgroundExperiencing parental stress is common among parents of children of all ages and is elevated in families characterized by stressors such as poverty, mental health problems, and developmental problems. The Parental Stress Scale (PSS) is a short measure for the assessment of perceived stress resulting from being a parent.MethodsThis study examines the construct validity and psychometric properties of the Danish PSS using Rasch and graphical loglinear Rasch models in a sample of parents of 2–18-year-old children with and without known behavior problems. We emphasized analyses of differential item functioning, to ascertain whether the scale yields unbiased scores for subgroups of parents.ResultsThe 18-item PSS did not fit the Rasch model or a graphical loglinear Rasch model. After dichotomizing item responses and eliminating items 2 and 11, we found the PSS to consist of two distinct subscales measuring parental stress and lack of parental satisfaction. For the total sample, the Parental Stress subscale fit a very complex graphical loglinear Rasch model with differential item functioning relative to parental education and whether children had behavior problems or not. The Lack of Parental Satisfaction subscale fit a simple graphical loglinear Rasch model with differential item functioning only relative to subsample. When dividing into subsamples of parents of children with and without behavior problems, the Parental Stress subscale fit a simple graphical loglinear Rasch model, though still with differential item functioning, while the Lack of Parental Satisfaction subscale fit the Rasch model in each subsample of parents. Both subscales performed best for parents of children with behavior problems.ConclusionsThe PSS should be used in a 16-item version and scored as two subscales. The PSS appears better suited for use among parents of children with behavior problems than within a sample without any known difficulties.

Psychometric evaluation of the Interpersonal Needs Questionnaire (INQ) using item analysis according to the Rasch model.

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.

Measuring stress in Australia: validation of the perceived stress scale (PSS-14) in a national sample

BackgroundIn Australia, the stress levels have increased over the years, impacting on the physical and mental health of the general population. The aim of the present study was to evaluate the validity and reliability of the PSS-14 in an Australian population.MethodsThe PSS-14 was applied to a large national sample comprising 3857 Australians in the population-based cross-sectional study Australia’s National Survey of Adult Oral Health 2004–2006. The psychometric properties analyzed with the Rasch model and Graphical Log-linear Rasch models were: model fit, item fit, local dependence, differential item functioning, unidimensionality, reliability, targeting and criterion validity.ResultsThe PSS-14 did not fit the pure RM (χ2 (55) = 3828.3, p = < 0.001) and the unidimensionality of the whole scale was rejected (p = < 0.001). The Perceived Stress (χ2 (27) = 1409.7, p = < 0.001) and Perceived Control (χ2 (27) = 713.4, p = < 0.001) subscales did not fit the pure RM. After the deletion of two items, the Perceived Stress subscale (χ2 (96) = 94.4, p = 0.440) fitted a GLLRM, while the Perceived Control scale (χ2 (55) = 62.50, p = 0.224) fitted a GLLRM after the exclusion of four misfitting items.ConclusionsThe Perceived Stress subscale displayed adequate psychometric properties after the deletion of two items; however, the majority of problems centered around the Perceived Control subscale. The presence of differential item functioning among four items indicates that adjustment of total scores is required to avoid measurement bias. Recommendations for future applications in Australia are provided.

Measuring Social Support among Soldiers with the Experienced Post-Deployment Social Support Scale (EPSSS): A Rasch-Based Construct Validity Study

Perceived social support following deployment is a known buffer against post-deployment adverse mental health outcomes. Given contextual sensitivity of social support measures, scales that address specific social support needs of soldiers in the first months after home coming should be developed and validated. In a sample of 553 soldiers deployed to Afghanistan at two different time points (2009 and 2013, respectively), we selected items for and tested the construct validity of an 8-item measure of experienced post-deployment social support (experienced post-deployment social support scale; EPSSS). Within the item response theory framework, we used Rasch models (RM) to conduct item analysis with an emphasis on testing for differential item functioning (DIF) across background variables such as previous deployments and cohort. In short, we found that the scale did not fit the Rasch model, but with exclusion of two items, a 6-item version of the scale did fit an extended graphical loglinear Rasch model (GLLRM) with only one instance of DIF, for which the score can be adjusted. We also demonstrated that when applied as a scale, the DIF will not affect the results substantially. Hence, we conclude that the constructed 6-item EPSSS can be validly applied without score correction to assess the level of social support in Danish soldiers after home coming.

Measuring higher education students’ perceived stress: An IRT-based construct validity study of the PSS-10

The Perceived Stress Scale (PSS-10) is widely used. Factor-analytic studies have reported a two-dimensional structure (Perceived Stress and Perceived Lack of Control subscales), however, few studies have employed Item Response Theory (IRT) or focused on the issue of differential item functioning (DIF). The Rasch Model (RM) for ordinal data and graphical loglinear Rasch models (GLLRM) were used with data from 1,552 technical and psychology university students. After elimination of item 6 the two subscales were found each to fit a GLLRM. However, lack of conditional independence of the items (LD) and equal item functioning (DIF) were found. The findings point to the need for further construct validity studies of the PSS-10 subscales focusing on the issues of DIF and LD.

Assessment of family functioning in families with a child diagnosed with type 1 diabetes: Validation and clinical relevance of the general functioning subscale of the McMaster family assessment device.

Type 1 diabetes (T1D) can have a negative effect on family functioning, which is associated with deterioration in metabolic control. Therefore, a valid tool for assessing family functioning is clinically relevant. We assessed the quality and validity of the Danish general functioning (GF) subscale of the family assessment device (FAD). Additionally, we investigated GF scores among adolescents with T1D and their parents and the relationship between family functioning and background variables, including metabolic control. All Danish families with a child diagnosed with T1D (N = 1997) were invited to participate in a web-based survey. In total, 616 adolescents (aged 12-17 years) and 1035 parents (of children aged 2-17 years) responded. The quality and validity of measurements made using the GF subscale were assessed using the Rasch model and graphical log-linear Rasch models (GLLRMs). Differences among GF responses were also assessed using GLLRMs. The relationships between GF scores and background variables were examined by multivariate analyses. A dichotomized version of the GF subscale provided essentially valid measures of family functioning. Furthermore, the GF subscale measured family functioning most accurately in families with worse family functioning than in our population. To accurately characterize family functioning, it is important to take both parent's and adolescent's perceptions into account. Family functioning was associated with glycated hemoglobin (HbA1c) levels, and discrepancies in family functioning were associated with higher HbA1c levels. A dichotomized GF subscale is useful for assessment of family functioning. Parent's and adolescent's scores should be kept separate. Family functioning is associated with HbA1c levels.

Construct validity of a service-setting based measure to identify mental health problems in infancy

Accumulating research document the needs of intervention towards mental health problems in early childhood. The general child health surveillance offers opportunities for early detection of mental health vulnerability, conditioned the availability of feasible and validated measures. The Copenhagen Infant Mental Health Questionnaire, CIMHQ, was developed to be feasible for community health nurses and comprehensive regarding the range of mental health problems seen in infancy. Previous testing of the CIMHQ has documented feasibility and face validity. The aim was to investigate the construct validity of the general population measure by using the Rasch measurement models, and to explore the differential functioning of the CIMHQ relative to a number of characteristics of the infants, local independence of items, and possible latent classes of infants. CIMHQ was tested in 2,973 infants from the general population, aged 9–10 months. The infants were assessed by community health nurses at home visits, in the period from March 2011 to December 2013. Rasch measurement models were used to investigate the construct validity of the CIMHQ. Analyses showed an overall construct valid scale of mental health problems, consisting of seven valid subscales of specific problems concerning eating, sleep, emotional reactions, attention, motor activity, communication, and language, respectively. The CIMHQ fitted a graphical loglinear Rasch model without differential item function. Analyses of local homogeneity identified two latent classes of infants. A simple model with almost no local dependency between items is proposed for infants with few problems, whereas a more complicated model characterizes infants with more problems. The measure CIMHQ differentiates between infants from the general population with few and more mental health problems, and between subgroups of problems that potentially can be targets of preventive intervention.

Validation of a health screening questionnaire for primary care using Rasch models

BackgroundHealth inequality is on the rise due to various social and individual factors. While preventive health checks (PHC) aim to counteract health inequality, there is robust evidence against the use of PHC in general practice. It is unknown which factors can identify persons who will benefit from preventive interventions that are more beneficial than harmful. Hence, valid screening instruments are needed.MethodsThe aim of this study was to assess the psychometric properties of a screening questionnaire (SQ-33), which targets vulnerable persons in primary care practice who can benefit from preventive consultations. Survey data were acquired from 20 primary care clinical practices in the Northern Region of Jutland, Denmark. Respondents were 2056 persons between 20 and 44 years old who, for any reason, consulted their family doctor. The psychometric properties of the SQ-33 were assessed using Rasch item response modelling. Follow-up analysis was performed on a subsample of 364 persons one year subsequent to initial inclusion, in order to assess responsiveness and predictive validity using a general health anchor item.ResultsTwenty-three of the SQ-33 items in four subscales fit a Graphical loglinear Rasch model (GLLRM) at baseline and follow-up, thus confirming the scaling properties. The modified 23-item version (HSQ-23) revealed superior responsiveness and predictive validity compared with the SQ-33.ConclusionsThe Health Screening Questionnaire (HSQ-23) was shown to possess adequate psychometric properties and responsiveness and can thus be used as an outcome measure in preventive intervention studies. Future study should address whether the HSQ-23 successfully identifies patients who will benefit from PHC consultations.

Psychometric properties of the Danish Parental Stress Scale: Rasch analysis in a sample of mothers with infants.

The Parental Stress Scale (PSS) was developed as a short measure of perceived stress resulting from being a parent. The current study examined the psychometric properties of the Danish version in a sample of 1110 mothers of children aged 0 to 12 months using Rasch models. Emphasis was placed on the issues of uni-dimensionality and absence of differential item functioning relative to the age and educational level of the mothers. Results showed that no adequate fit could be established for the full PSS scale with 18 dichotomized items. Further analyses showed that items 2 and 11 had to be eliminated from the scale, and that the remaining items did not make up a unidimensional PSS scale, but two subscales measuring different aspect of parental stress: a 9-item scale measuring parental stress and a 7-item scale measuring lack of parental satisfaction. Fit to the Rasch model could not be established for any of the two subscales. For the parental stress subscale, we found evidence of local dependence for four item pairs (3 and 4, 9 and 10, 10 and 16, 12 and 16), as well as evidence of two items functioning differentially: item 16 relative to level of education, and item 3 relative to both age and educational level. For the lack of parental satisfaction subscale, we found evidence of local dependence between some two pairs (1 and 17, 17 and 18), but no evidence of differential item functioning. Both subscales fit graphical loglinear Rasch models adjusting for local dependence and differential item functioning. Plotting the adjusted subscale scores against one another showed that the two-scale solution provides additional information, as some mothers are stressed but not lacking in parental satisfaction.

Measurement of alienation among adolescents: construct validity of three scales on powerlessness, meaninglessness and social isolation

BackgroundPsychological alienation is an important concept in the study of adolescents’ health and behavior but no gold standard for measuring alienation among adolescents exists. There is a need for new scales with high validity for use in adolescent health and social research. The purpose of the present study was to develop and validate alienation scales in accordance with Seeman’s conceptualization of alienation focusing on three independent variants specifically relevant in adolescent health research: powerlessness, meaninglessness and social isolation.MethodsCross-sectional data from 3083 adolescents aged 13 to 15 years from the Danish contribution to the cross-national study Health Behaviour in School-aged Children (HBSC) were used. We identified and developed items, addressed content and face validity through interviews, and examined the criterion-related construct validity of the scales using graphical loglinear Rasch models (GLLRM).ResultsThe three scales each comprised three to five face valid items. The powerlessness scale reflected the adolescent’s expectancy as to whether his/her behavior can determine the outcome or reinforcement he/she seeks. The meaninglessness scale reflected the expectancy as to whether satisfactory predictions regarding the effects of one’s behavior are possible. Finally, the social isolation scale reflected whether the adolescent had a low expectancy for inclusion and social acceptance. All scales contained some uniform local dependency and differential item functioning. However, only to a limited degree, which could be accounted for using GLLRM. Thus the scales fitted GLLRMs and can therefore be considered to be essentially construct valid and essentially objective.ConclusionThe three alienation scales appear to be content and face valid and fulfill the psychometric properties of a good construct valid reflective scale. This suggests that the scales may be appropriate in future large-scale surveys to examine the relation between alienation and a range of adolescent health outcomes such as health, behavior and wellbeing.

Validity and Reliability of the Major Depression Inventory for Persons With Dual Sensory Loss.

Background and ObjectivesResearch has shown that dual sensory loss is a risk factor for depression in older adults. However, validated measures of depression for people with dual sensory loss are lacking. The purpose of the present study was to investigate the construct validity and reliability of the Major Depression Inventory for use among elderly persons with acquired dual sensory loss.Research Design and MethodsA cross-sectional questionnaire survey was conducted in a national sample of people ≥50 years of age with functional acquired dual sensory loss. Of the invited participants, 302 (66%) returned the questionnaire and 207 complete cases were included for analysis. Rasch models and graphical log-linear Rasch models were used for item analysis. Lack of differential item functioning was tested relative to severity of vision and hearing impairment, mode of questionnaire completion, age, sex, comorbidity, instrumental activities of daily living, social position, and cohabitation status.ResultsThe 10-item Major Depression Inventory did not fit the Rasch model. An 8-item version, excluding the items “feeling sad” and “sleep problems,” fit a graphical log-linear Rasch model. No evidence of differential item functioning was discovered, thus the 8-item Major Depression Inventory was measurement invariant across severity of impairments and mode of completing the questionnaire. The overall reliability was 0.81 and ranged from acceptable to good for all subgroups of participants, except males with severe hearing impairment and low functional status. Consequently, the 8-item version of the Major Depression Inventory was considered construct valid and reliable within the frame of reference.Discussion and ImplicationsAn 8-item version of the Major Depression Inventory can be used to screen for depressive symptoms in elderly persons with acquired dual sensory loss.

Item analysis using Rasch models confirms that the Danish versions of the DISABKIDS\xae chronic-generic and diabetes-specific modules are valid and reliable

BackgroundType 1 Diabetes (T1D) has a negative impact on psychological and overall well-being. Screening for Health-related Quality of Life (HrQoL) and addressing HrQoL issues in the clinic leads to improved well-being and metabolic outcomes. The aim of this study was to translate the generic and diabetes-specific validated multinational DISABKIDS® questionnaires into Danish, and then determine their validity and reliability.MethodsThe questionnaires were translated using a validated translation procedure and completed by 99 children and adolescents from our diabetes-department; all diagnosed with T1D and were aged between 8 and 18 years old. The Rasch and the graphical log linear Rasch model (GLLRM) were used to determine validity. Monte Carlo methods and Cronbach’s α were used to confirm reliability.ResultsThe data did not fit a pure Rasch model but did fit a GLLRM when item six in the independence scale is excluded. The six subscales measure different aspects of HrQoL indicating that all the subscales are necessary. The questionnaire shows local dependency between items and differential item functioning (DIF). Therefore age, gender, and glycated hemoglobin (HbA1c) levels must be taken into account when comparing HrQoL between groups.ConclusionsThe Danish versions of the DISABKIDS® chronic-generic and diabetes-specific modules provide valid and objective measurements with adequate reliability. These Danish versions are useful tools for evaluating HrQoL in Danish patients with T1D. However, guidelines on how to manage DIF and local independence will be required, and item six should be rephrased.

Item response drift in the Family Affluence Scale: A study on three consecutive surveys of the Health Behaviour in School-aged Children (HBSC) survey

Comparable data on socio-economic position (SEP) is essential to international studies on health inequalities. The Health Behaviour in School-aged Children (HBSC) has used the Family Affluence Scale (FAS) on material assets. The present study used data collected from adolescents in eight countries in 2002, 2006 and 2010, and examined the construct validity of the FAS, by focusing on changes in item responses over time. The analyses reported the changes in means in item responses, and fitted models which estimated differential item functioning (DIF), and local dependency (LD) between items. DIF and LD were analysed by Graphical Log-Linear Rasch Models (GLLRMs), and changes in the measurement properties of the FAS over time and between countries were assessed. The results showed that the FAS items have changed their measurement properties between 2002 and 2010, and caution is warranted in studies comparing the FAS between different time points.