Item Response Theory Methodology Research Articles

Item performance of the scale for the assessment and rating of ataxia in rare and ultra-rare genetic ataxias.

The Scale for the Assessment and Rating of Ataxia (SARA) is widely used for assessing the severity and progression of genetic cerebellar ataxias. SARA is now considered a primary end point in several ataxia treatment trials, but its underlying composite item measurement model has not yet been tested. This work aimed to evaluate the composite properties of SARA and its items using item response theory (IRT) and to demonstrate its applicability across even ultra-rare genetic ataxias. Leveraging SARA subscores data from 1932 visits from 990 patients of the Autosomal Recessive Cerebellar Ataxias (ARCA) registry, we assessed the performance of SARA using IRT methodology. The item characteristics were evaluated over the ataxia severity range of the entire ataxia population as well as the assessment validity across 115 genetic ARCA subpopulations. A unidimensional IRT model was able to describe SARA item data, indicating that SARA captures one single latent variable. All items had high discrimination values (1.5-2.9) indicating the effectiveness of the SARA in differentiating between subjects with different disease statuses. Each item contributed between 7% and 28% of the total assessment informativeness. There was no evidence for differences between the 115 genetic ARCA subpopulations in SARA applicability. These results show the good discrimination ability of SARA with all of its items adding informational value. The IRT framework provides a thorough description of SARA on the item level, and facilitates its utilization as a clinical outcome assessment in upcoming longitudinal natural history or treatment trials, across a large number of ataxias, including ultra-rare ones.

Development of a Short Form Assessment Combining the Fugl-Meyer Assessment–Upper Extremity and the Wolf Motor Function Test for Evaluating Stroke Recovery

ObjectiveTo use Rasch methodologies to combine the items of the Fugl-Meyer Assessment–Upper Extremity (FMA-UE, motor skill) and the Wolf Motor Function Test (WMFT, motor function) onto a single measurement metric and create an FMA-UE+WMFT short form. DesignSecondary analysis of preintervention data from 2 upper extremity stroke rehabilitation trials. Confirmatory factor analysis and Rasch rating scale analysis were first applied to examine the properties of the pooled item bank and then item response theory methodologies were used to develop the short form. Confirmatory factor analysis and Rasch analysis were then applied to the short form to examine the dimensionality and measurement properties. SettingOutpatient academic medical research center. ParticipantsData from 167 participants who completed the FMA-UE and WMFT (rating scale score) were pooled (N=167). Participants were eligible if they had a stroke ≥3 months prior and had upper extremity (UE) hemiparesis and excluded if they had severe UE hemiparesis, severe UE spasticity, or UE pain. InterventionNot applicable. Main Outcome MeasuresThe dimensionality and measurement properties of the pooled 30-item FMA-UE and the 15-item WMFT and short form were examined. ResultsFive items from the pool of 45 items were misfit and were removed. The 40-item pool demonstrated adequate measurement properties. A 15-item short form was then developed and met rating diagnostic scale criteria. All items on the 15-item short form met the Rasch fit criteria, and the assessment met criteria for reliability (Cronbach alpha=.94), separation (person separation = 3.7), and strata (number of strata = 5). ConclusionsItems from the FMA-UE and WMFT can be pooled to create a psychometrically sound 15-item short form.

A New Method for Calculating Consumer Price Indices: Incorporating Consumer Perceptions and Attitudes with Item Response Theory

This paper presents a conceptual approach to improve consumer price indices (CPI) by incorporating consumers' perceptions and attitudes towards pricing. The proposed approach uses item response theory (IRT) and aims to overcome the limitations of existing CPI methods. The paper provides a comprehensive literature review of existing CPI methods and discusses their potential advantages and limitations. The methodology covers survey design, data collection and data analysis, with a focus on IRT theory and methodology. This approach has the potential to improve the accuracy of CPIs by incorporating consumers' perceptions and attitudes towards pricing. However, the paper also acknowledges potential limitations, including the need for a representative sample and the complexity of the IRT model. Overall, this conceptual paper contributes to the literature on CPIs by proposing a new approach that addresses the limitations of existing methods and has the potential to provide more accurate measures of inflation. The ideas presented in this paper could serve as a basis for future research and inform the development of new CPI methods.

Scale Development Based on Item Response Theory: A Systematic Review

Classical test theory (CTT) and item response theory (IRT) are two fundamental approaches used in scale development research. Although CTT is the preferred methodology in scale development research in the Republic of Turkey, the IRT methodology has started to gain traction in recent years. In this study, we used the systematic review methodology to review scale development research in Turkey that used the IRT procedures. Results revealed that most of the studies were conducted in 2017. Most of the studies have a sufficient sample size. Exploratory factor analysis was used more than confirmatory factor analysis. Some studies failed to choose the proper IRT model, report and interpret item parameters, check IRT assumptions, and report and interpret information functions. We recommend some practical considerations to researchers in terms of IRT assumptions.

PSYCHOMETRIC PROPERTIES OF A NOVEL MEASURE OF FINANCIAL ABUSE OF OLDER ADULTS

Abstract Background and Objectives Elder abuse, or mistreatment affects at least 1 in 10 older adults. Financial abuse, or exploitation, of older adults is among the most commonly reported forms of abuse. Few validated measures exist to measure this construct. We aim to present a new psychometrically validated measure of financial abuse of older adults.Research Design and Methods Classical test theory and item response theory methodologies were used to examine a five-item measure of financial abuse of older adults, administered as part of the New York State Elder Mistreatment Survey. Results Factor analysis revealed a single factor best fits the data, which we labeled as financial abuse. Moreover, IRT analyses revealed that these items discriminated well between abused and non-abuse persons and provided information at high levels of the latent trait θ, as is expected in cases of abuse. Discussion and Implications: The FIVE has acceptable psychometric properties and has been used successfully in large scale survey research. We recommend this measure as an indicator of financial abuse in elder abuse, or mistreatment prevalence research studies.

Modeling repeated self-reported outcome data: A continuous-time longitudinal Item Response Theory model.

Item Response Theory (IRT) models have received growing interest in health science for analyzing latent constructs such as depression, anxiety, quality of life or cognitive functioning from the information provided by each individual's items responses. However, in the presence of repeated item measures, IRT methods usually assume that the measurement occasions are made at the exact same time for all patients. In this paper, we show how the IRT methodology can be combined with the mixed model theory to provide a longitudinal IRT model which exploits the information of a measurement scale provided at the item level while simultaneously handling observation times that may vary across individuals and items. The latent construct is a latent process defined in continuous time that is linked to the observed item responses through a measurement model at each individual- and occasion-specific observation time; we focus here on a Graded Response Model for binary and ordinal items. The Maximum Likelihood Estimation procedure of the model is available in the R package lcmm. The proposed approach is contextualized in a clinical example in end-stage renal disease, the PREDIALA study. The objective is to study the trajectories of depressive symptomatology (as measured by 7 items of the Hospital Anxiety and Depression scale) according to the time from registration on the renal transplant waiting list and the renal replacement therapy. We also illustrate how the method can be used to assess Differential Item Functioning and lack of measurement invariance over time.

Testing the psychometric properties of a short skills inventory for students looking for their first job

BackgroundIn the last two decades, the transformations that have affected the business world have had a great impact on professional performance standards. As such, they have contributed significantly to increasing concerns regarding employability. Particularly, these concerns are even more worrying among students who are looking for their first job. Consequently, this leads organizations to question whether the skills these candidates have are sufficient and adequate for them to enter the job market. Although it is a problem that deserves an urgent response, it is still poorly understood amongst academics, which is why it continues to be essential to define and signal which skills candidates should develop in order to guarantee a better person-function fit. Hereupon, the present study aims at the construction and validation of a short skills inventory for students who are looking for their first job. This inventory will allow alignment between candidates' skills and the level of performance expected by their future employers.MethodsThe development of the short skills inventory for students looking for their first job was based on Classical test theory and Item response theory methodologies. Specifically, its developmental process encompassed three studies. Study 1, comprising a qualitative scope, dealt with the development and construction of the items (n = 97). Study 2, of an exploratory nature, was intended to evaluate the psychometric properties of the instrument (n = 173). Finally, Study 3, of a confirmatory nature, was aimed at validating the results gathered from the Exploratory factor analysis (n = 407).ResultsThis inventory is a valuable asset for the selection of students who are looking for their first job. The analyzes carried out over the various studies show that this instrument has satisfactory psychometric properties, and, as such, is a valid and reliable instrument and an alternative to the instruments currently used in the recruitment and selection processes.ConclusionsThe construction of this short skills inventory brings theoretical and practical benefits. In short, it contributes to reducing Portugal’s gap regarding psychological assessment upon selection considering the lack of validated and verified instruments for students looking for their first job.

Development of a Short Form Assessment of Upper Extremity Motor Ability for Individuals Post Stroke

Research Objectives To develop a short form assessment that combines items from the Fugl Meyer Assessment-Upper Extremity (FMA) and the Wolf Motor Function Test (WMFT) to provide a more comprehensive and precise measure of UE motor ability post stroke. Design We used a convenience sample of pre-intervention data from two upper extremity rehabilitation trials conducted with stroke survivors. Factor analysis and the Rasch rating scale model were applied to examine the properties of the full item bank prior to the development of the short form. Setting Outpatient, academic research center. Participants Data were pooled since the parent studies had similar eligibility criteria. Participants were included in the studies if they experienced a stroke ≥ 3 months prior and had UE hemiparesis. Participants were excluded if they had severe hemiparesis, severe spasticity (Modified Ashworth Scale >3 in elbow, wrist, or fingers), or reported UE pain. 167 individuals with stroke who completed both the WMFT and FMA were included. Interventions N/A. Main Outcome Measures Data from the 30-item FMA and the 15-item WMFT (rating scale score) were analyzed using factor analysis to ensure unidimensionality. Item response theory methodologies were used to develop the short form. The Rasch rating scale model was applied to examine the measurement properties. Results A 15-item short form was developed. Item infit statistics (Mnsq) ranged from 0.63-1.35 and point measure correlations ranged from 0.39-0.90. Person reliability was 0.93 and the person separation index was 3.7 indicating the measure can separate between 5 statistically different strata. Conclusions Items from the FMA and WMFT can be combined to provide a precise measure of UE motor ability. The short form demonstrated acceptable psychometric properties. Author(s) Disclosures The authors have no conflicts of interest to disclose. To develop a short form assessment that combines items from the Fugl Meyer Assessment-Upper Extremity (FMA) and the Wolf Motor Function Test (WMFT) to provide a more comprehensive and precise measure of UE motor ability post stroke. We used a convenience sample of pre-intervention data from two upper extremity rehabilitation trials conducted with stroke survivors. Factor analysis and the Rasch rating scale model were applied to examine the properties of the full item bank prior to the development of the short form. Outpatient, academic research center. Data were pooled since the parent studies had similar eligibility criteria. Participants were included in the studies if they experienced a stroke ≥ 3 months prior and had UE hemiparesis. Participants were excluded if they had severe hemiparesis, severe spasticity (Modified Ashworth Scale >3 in elbow, wrist, or fingers), or reported UE pain. 167 individuals with stroke who completed both the WMFT and FMA were included. N/A. Data from the 30-item FMA and the 15-item WMFT (rating scale score) were analyzed using factor analysis to ensure unidimensionality. Item response theory methodologies were used to develop the short form. The Rasch rating scale model was applied to examine the measurement properties. A 15-item short form was developed. Item infit statistics (Mnsq) ranged from 0.63-1.35 and point measure correlations ranged from 0.39-0.90. Person reliability was 0.93 and the person separation index was 3.7 indicating the measure can separate between 5 statistically different strata. Items from the FMA and WMFT can be combined to provide a precise measure of UE motor ability. The short form demonstrated acceptable psychometric properties.

Screening for Intimate Partner Violence in Family Mediation: An Examination of Multiple Methodological Approaches Using Item Response Theory.

Many divorcing/separating parties seeking mediation to resolve family-related issues report intimate partner violence (IPV) victimization from the other party in the case. It is imperative that mediation staff screen parties for IPV so they can make informed decisions regarding how to proceed with mediation. Existing IPV screens for mediation have significant limitations. We examined three methodological approaches using item response theory that address these limitations by increasing the efficiency and clinical utility of an existing standardized IPV screen for mediation, the Mediator's Assessment of Safety Issues and Concerns (N = 904 mediating parties). We identified three subsets of items, with initial evidence for their validity, focused on helping mediation staff identify high levels of IPV or parties at risk for potentially negative mediation outcomes or needing specialized safety accommodations in mediation. Clinical recommendations are provided indicating which approach is most promising to be used in mediation settings. Overall, findings help advance understanding of how item response theory methodology can enhance the precision of IPV screening in mediation.

La mesure de la personnalité à l’aide du Big Five Inventory français (BFI-Fr) est-elle invariante selon le genre et l’activité des répondants ?

ObjectivesThe BFI-Fr is an effective tool to assess the five dimensions of the five-factor model of personality. The psychometric qualities are excellent in several validation studies. However, because the inconsistency of certain items may be due to a lack of invariance between groups, we examined this invariance according to the gender and activity of the respondents. MethodsThe sample consists of 1904 participants (1232 women and 672 men; 1159 students and 745 professionals). Recruitment was done by “snowball” from different studies conducted over four years. Respondents completed the BFI-Fr. The 45 items were corrected for the acquiescence bias. The Item Response Theory methodology was used to test the invariance using the differential item functioning (DIF) test. The T scores were subject to ANCOVA and correlations to compare the differences between subgroups. ResultsWhatever the subsample, we found the same five-factor structure (similarities were especially high for C). The cumulative explained variances are comparable for all groups. The functioning of eight items varied between men and women; and six between activity groups, however, all but one DIF values were low. No item in domain A varied in its measure. ANCOVA results showed that women have higher A and N scores than men and that professionals have higher C and lower N scores than students. There is no interaction effect between gender and activity. When we removed the non-invariant items, the effect of gender became significant in favor of women on dimension C even if the difference remained minimal. The difference by activity on N became non-significant. There was a very strong link between activity and age and between gender and activity: in the sample, women were more often students and vice versa. ConclusionsOverall and once again, the structure and internal consistency of the Big Five as measured by the BFI-Fr was replicated in new samples. There was a differential functioning of 12 items out of 45 (about a quarter). These differences were small since only one was of moderate magnitude. The deletion of these items did not strongly change the mean comparisons between groups. Therefore, our results do not call into question the usefulness of the BFI-Fr but invite to control the extent of this differential functioning. In all cases (with or without the non-invariant items) the analyses showed significant gender differences for A and N, differences which are typically found in many studies. Students and professionals differ in their levels of C and E. Certain inconsistencies are probably due to the translation from American to French, since the BFI-Fr is based on the lexical approach (in this context, item content was somewhat dependent of languages peculiarities). Thus, the BFI-Fr allows a robust evaluation of the five dimensions but requires a prior control of the invariance of item functioning in order to ensure that the intergroup differences in E-A-C-N-O mean scores do not reflect a psychometric artifact but genuine personality differences.

The association between protein consumption from animal and plant sources with psychological distress in older people in the Mediterranean region

BACKGROUND: The potential for diet to prevent and treat mental health conditions is an exciting area of investigation; however, the impact of different protein sources on mental health outcomes is unclear. OBJECTIVE: To evaluate the association between dietary protein intake and psychological distress, in people aged >50 years of age, living in Greece. METHODS: A combined data set of older people living in the Athens metropolitan area and 20 Greek islands, from the ATTICA (n = 1,128) and MEDIS (n = 2,221) population-based cross-sectional studies was developed. Anthropometric, clinical and socio-demographic and lifestyle characteristics, and protein consumption (total, animal, plant) consumed based on validated FFQ, were derived through standard procedures and questionnaires. “Psychological distress” (PDS) was assessed as a combined variable representing symptoms of depression and anxiety using Item Response Theory methodology and fitting a Graded Response Model. RESULTS: Animal protein, but not plant protein intake, was associated with higher PDS following adjustment for age, sex, education level, Mediterranean diet adherence and physical activity (b±SE: 0.399±0.090, p = 0.003). Following analysis by Mediterranean diet adherence level, among low adherers, animal protein intake was positively associated with PDS (b±SE: 1.119±0.174, p = 0.003), and no associations were observed in moderate or high adherence groupsin regards to plant protein intake and PDS. CONCLUSIONS: Animal protein intake is associated with PDS, suggesting a bi-directional relationship, which may be influenced by Mediterranean diet adherence.

Validation of Short Form of Preferences for Routines Scale: Norms in Older Adults.

High level of preferences for routines is an indicator of psychological vulnerability in older adults. However, the psychometric properties of the Preferences for Routines Scale (PRS) initially validated in a small selected sample of older adults revealed a low Cronbach's α (.50) in the general elderly population. The present study aims to improve the PRS using the data from the "AMI" and "PAQUID" population-based studies. Among 718 older persons, the most discriminative items are identified using item response theory methodology. A short form of the PRS (PRS-S) included five of the ten items of the original scale and showed improved internal consistency and test-retest reliability. The factors associated with the PRS-S are similar to those found in previous studies. Norms are provided according to gender and educational level. The reduction of the number of items tends to facilitate its administration and promote its use in both clinical and epidemiologic research contexts.

Measuring Thwarted Belongingness and Perceived Burdensomeness in Clinically Depressed and Suicidal Youth: Refinement and Reduction of the Interpersonal Needs Questionnaire.

The Interpersonal-Psychological Theory of Suicide (IPTS) posits two constructs (thwarted belongingness (TB) and perceived burdensomeness (PB)) contribute to suicide ideation. These constructs are typically measured by the Interpersonal Needs Questionnaire (INQ); however, available INQ versions have demonstrated poor psychometric properties with youth. This study examined the INQ using Item Response Theory (IRT) to refine and reduce the scale for clinically depressed and suicidal youth. Participants were 378 youth (Age M (SD)=14.78 (1.41), 82.54% female) who completed the INQ. The INQ contains 25 items across two subscales (i.e., TB and PB) rated on a 7-point Likert-type scale. Rating scale performance, dimensionality, model fit, and instrument-level statistics were examined using IRT methodology. Post hoc analyses were performed to further reduce the scale. The INQ was reduced from 25 to 10 items (five per subscale), and response options were refined to four choices. Correlations between original and IRT-refined items were large (r=.97 for PB; r=.98 for TB). Additional item-level (e.g., fit, difficulty) and instrument-level (e.g., dimensionality) characteristics were examined. The newly refined INQ resulted in improved scale reliability and validity. The psychometrically improved INQ can assist clinicians and researchers identify adolescents at risk of experiencing suicide ideation.

Subjective Cognitive Decline Prediction of Mortality: Results from the Einstein Aging Study.

The relation of pre-dementia stages to mortality has not been fully explored. Previous work examining subjective cognitive decline (SCD) and mortality is limited and mixed regarding methods used and consistency of findings. To examine SCD and mortality in a longitudinal, community-based cohort, using item response theory (IRT) methodology to form a composite SCD measure. Also, to assess whether this relationship was independent of clinical cognitive status. The Einstein Aging Study is a diverse longitudinal cohort of adults aged ≥70. SCD items were extracted from baseline CERAD questionnaires and a composite score was formed using IRT methodology. A total of 1,741 participants with complete data were clinically diagnosed as cognitively normal, or as having amnestic mild cognitive impairment (aMCI), nonamnestic mild cognitive impairment (naMCI), or dementia. 645 deaths occurred over a period of 8,912 person-years of follow-up. Cox proportional hazard models predicted time to death adjusting for covariates. A one standard deviation unit increase in level of SCD was associated with >20% higher risk of mortality. However, when models were adjusted for clinical cognitive status, the association was no longer significant. Both dementia and aMCI predicted mortality. Furthermore, when analyses focused only on those without cognitive impairment, SCD level did not predict mortality. The association of SCD with mortality may be due to the association of SCD with clinical cognitive status. Thus, SCD may be used as a community-based screen to initially identify those with cognitive impairment who may be at greatest risk for death.

Differential change on depressive symptom factors with antidepressant medication and cognitive behavior therapy for major depressive disorder

BackgroundMajor depressive disorder (MDD) is a heterogeneous condition and individual patients are likely to be differentially responsive to specific treatments. In an exploratory factor analysis of three rating scales, the Genome-based Therapeutic Drugs for Depression (GENDEP) trial identified three factors that were differentially associated with outcome to nortriptyline and escitalopram. However, this factor analysis has neither been replicated or applied to a psychotherapy treatment. MethodsWe replicated the GENDEP analytic method in the Emory Predictors of Remission to Individual and Combined Treatments (PReDICT) study. The 17-item Hamilton Depression Rating Scale, Montgomery Asberg Depression Rating Scale, and Beck Depression Inventory were administered to 306 MDD patients in the PReDICT study, which randomized previously untreated adults to 12 weeks of treatment with cognitive behavior therapy (CBT), escitalopram, or duloxetine. Utilizing Item Response Theory methodologies, factor scores were derived from the three scales and the efficacy of the three treatments was compared for the identified factor scores. ResultsFour factors were identified: “Despair,” “Mood and Interest,” “Sleep,” and “Appetite.” These factors closely aligned with the factors identified in GENDEP. Compared to CBT, escitalopram and duloxetine produced more rapid but ultimately similar improvement on the Despair and Mood and Interest factors; no significant differences between treatments emerged on the other factors. LimitationsThe scales contained differing numbers of items pertaining to specific depressive symptoms. ConclusionThe heterogeneity of MDD can be parsed into a consistent factor structure, with the factors showing differential rapidity, but ultimately similar, improvement across treatments.

Item Response Theory Analysis to Assess Dimensionality of Substance Use Disorder Abuse and Dependence Symptoms

Item response theory (IRT) based studies conducted on diverse samples showed a single dominant factor for DSM-III-R and DSM-IV substance use disorder (SUD) abuse and dependence symptoms of alcohol, cannabis, sedative, cocaine, stimulants, and opiates use disorders. IRT provides the opportunity, within a person-centered framework, to accurately gauge each person's severity of disorder that, in turn, informs required intensiveness of treatment. The aim of this study was to determine whether the SUD symptoms indicate a unidimensional trait or instead need to be conceptualized and quantified as a multidimensional scale. The sample was composed of families of adult SUD+ men (n=349), and SUD+ women (n=173), who qualified for DSM-III-R diagnosis of substance use disorder (abuse or dependence) and families of adult men and women who did not qualify for a SUD diagnosis (SUD- men: n=190, SUD- women: n=133). An expanded version of the Structured Clinical Interview for DSM-III-R (SCID) was administered to characterize lifetime and current substance use disorders. Item response theory methodology was used to assess the dimensionality of DSM-III-R SUD abuse and dependence symptoms. A bi-factor model provided the optimal representation of the factor structure of SUD symptoms in males and females. SUD symptoms are scalable as indicators of a single common factor, corresponding to general (non-drug-specific, common) liability to addiction, combined with drug-specific liabilities. IRT methodology used to quantify the continuous general liability to addiction (GLA) latent trait in individuals having SUD symptoms was found effective for accurately measuring SUD severity in men and women. This may be helpful for person-centered medicine approaches to effectively address intensity of treatment.

Development and Validation of the Activities of Daily Living Short Form for Community-Dwelling Korean Stroke Survivors.

This study developed and validated a short form (SF) using activities of daily living (ADL) outcome measures from the Korea National Health and Nutrition Examination Survey (KNHANES) that can minimize survey administration burden for clinicians. This study utilized secondary data from the 2005 KNHANES with 422 community-dwelling stroke survivors. The KNHANES data were collected from April to June 2005 in South Korea. We created a 7-item SF from the 17 ADL questions in the survey using item response theory (IRT) methodologies. The precision and validity of the SF were compared to the full questionnaire of ADL items and the EuroQol-5D total score. Among the 17 ADL questions, 14 questions demonstrated unidimensional construct validity. Using IRT methodologies, a set of 7 items were selected from the full bank. The 7-item SF demonstrated good psychometric properties: high correlation with the full bank ( r = .975, p < .001), good internal consistency (Cronbach's α = .93), and a high correlation with the EuroQol-5D total score ( r = .678, p < .001). These findings indicate that a well-developed SF can precisely measure ADL performance capacity for stroke survivors compared to the full item bank, which is expected to reduce the administration burden of the KNHANES.

Further Simplification of the Simple Erosion Narrowing Score With Item Response Theory Methodology.

To further simplify the simple erosion narrowing score (SENS) by removing scored areas that contribute the least to its measurement precision according to analysis based on item response theory (IRT) and to compare the measurement performance of the simplified version to the original. Baseline and 18-month data of the Combinatietherapie Bij Reumatoide Artritis (COBRA) trial were modeled using longitudinal IRT methodology. Measurement precision was evaluated across different levels of structural damage. SENS was further simplified by omitting the least reliably scored areas. Discriminant validity of SENS and its simplification were studied by comparing their ability to differentiate between the COBRA and sulfasalazine arms. Responsiveness was studied by comparing standardized change scores between versions. SENS data showed good fit to the IRT model. Carpal and feet joints contributed the least statistical information to both erosion and joint space narrowing scores. Omitting the joints of the foot reduced measurement precision for the erosion score in cases with below-average levels of structural damage (relative efficiency compared with the original version ranged 35-59%). Omitting the carpal joints had minimal effect on precision (relative efficiency range 77-88%). Responsiveness of a simplified SENS without carpal joints closely approximated the original version (i.e., all Δ standardized change scores were ≤0.06). Discriminant validity was also similar between versions for both the erosion score (relative efficiency = 97%) and the SENS total score (relative efficiency = 84%). Our results show that the carpal joints may be omitted from the SENS without notable repercussion for its measurement performance.

Natural History of Dependency in the Elderly: A 24-Year Population-Based Study Using a Longitudinal Item Response Theory Model.

We aimed to describe the hierarchical structure of Instrumental Activities of Daily Living (IADL) and basic Activities of Daily Living (ADL) and trajectories of dependency before death in an elderly population using item response theory methodology. Data were obtained from a population-based French cohort study, the Personnes Agées QUID (PAQUID) Study, of persons aged ≥65 years at baseline in 1988 who were recruited from 75 randomly selected areas in Gironde and Dordogne. We evaluated IADL and ADL data collected at home every 2-3 years over a 24-year period (1988-2012) for 3,238 deceased participants (43.9% men). We used a longitudinal item response theory model to investigate the item sequence of 11 IADL and ADL combined into a single scale and functional trajectories adjusted for education, sex, and age at death. The findings confirmed the earliest losses in IADL (shopping, transporting, finances) at the partial limitation level, and then an overlapping of concomitant IADL and ADL, with bathing and dressing being the earliest ADL losses, and finally total losses for toileting, continence, eating, and transferring. Functional trajectories were sex-specific, with a benefit of high education that persisted until death in men but was only transient in women. An in-depth understanding of this sequence provides an early warning of functional decline for better adaptation of medical and social care in the elderly.

Methodological approach for assessing the potential of a rural tourism destination: An application in the province of Cáceres (Spain)

Evaluating the resources in a tourism destination is one of the previous tasks in the development of its comprehensive planning. There are many criteria to use in order to evaluate tourism resources; but, independently on the number of attributes considered the fact is that not every criterion is equally important in the process of evaluation and ranking of the tourism potential of a destination's resources. In contrast to other well-known methodologies, the aim of this paper is to propose a methodology to weight qualitative and hierarchical evaluation attributes by estimating a discrimination parameter. In this research, an item response theory (IRT) model is used, the graded response model, to estimate each attribute's discrimination coefficient. This parameter will be the basis to propose a weighting system for the entire set of attributes. Graded response model (GRM) will also allow establishing a hierarchy of resources by constructing a continuous latent scale, where it will be possible to position every analysed resource in the tourism destination. The applicability and robustness of the IRT methodology will be tested using data from rural tourism resources in the Spanish province of Cáceres.