Classical Test Theory Methods Research Articles

Validation of the shortened Perceived Medical Condition Self-Management Scale in patients with chronic disease.

Self-efficacy, or perceived competence, has been identified as an important factor in self-management behaviors and health outcomes in patients with chronic disease. Measures of self-management self-efficacy are currently available for multiple forms of chronic disease. One established measure is the 8-item Perceived Medical Condition Self-Management Scale (PMCSMS). This study investigated the use of the PMCSMS in samples of patients with a chronic disease to develop an abbreviated version of the scale that could be more readily used in clinical contexts or in large population health cohort studies. The PMCSMS was administered as either a generic scale or as a disease-specific scale. The results of analyses using item response theory and classical test theory methods indicated that using 4 items of the scale resulted in similar internal consistency (α = .70-0.90) and temporal stability (test-retest r = .75 after 2 to 4 weeks) to the 8-item PMCSMS (r = .81 after 2 to 4 weeks). The 4 items selected had the greatest discriminability among participants (α parameters = 2.49-3.47). Scores from both versions also demonstrated similar correlations with related constructs such as health literacy (r = .13-0.29 vs. 0.14-0.27), self-rated health (r = .17-0.48 vs. 0.26-0.50), social support (r = .21-0.32 vs. 0.25-0.34), and medication adherence (r = .20-0.24 vs. 0.20-0.25). The results of this study indicate that 4-item PMCSMS scores are equally valid but more efficient, and have the potential to be beneficial for both research and clinical applications. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Two valid and reliable work role functioning questionnaire short versions were developed: WRFQ 5 and WRFQ 10

ObjectiveThe study aims to develop and validate short versions of the work role functioning questionnaire v2.0 (WRFQ) that retain the measurement properties of the full-length 27-item questionnaire. Study design and settingSix cross-sectional Dutch samples (N = 2,433) were used, containing data on gender, self-rated health, job type, and WRFQ scores. Indicators from classical test theory and item response theory methods were used along with evaluation of translatability and conceptual considerations to identify short version candidate items. To ensure content validity, the item selection was made within the five-factor structure established for the WRFQ—leading to a 5-item and a 10-item short version. Bland-Altman analyses of agreement and interclass correlations with the full WRFQ were used to establish the best scoring procedure. Discriminant validity was evaluated for the short versions and compared with the full-length 27-item version. ResultsBoth short versions showed acceptable agreement with the full-length 27-item version using simple scoring procedures. Both also showed comparable or stronger validity than the full WRFQ in known group comparisons. ConclusionBoth short versions can be used to measure work role functioning in working samples with mixed clinical conditions and job types.

The 88-item Multiple Sclerosis Spasticity Scale: a Rasch validation of the Italian version and suggestions for refinement of the original scale

In multiple sclerosis (MS), the impact of spasticity on the patient's life is a key issue, and it is fundamental that existing tools measuring the patient's perspective undergo psychometric analysis and refinement to optimize confidence in their use in clinical practice and research. We examined-by Rasch analysis (RA)-the main metric characteristics of the 88-item Multiple Sclerosis Spasticity Scale (MSSS-88) to: (i) further validate its Italian version (MSSS-88-IT), previously validated through classical test theory methods only and (ii) independently verify the measurement properties of the original scale. MSSS-88 data from a convenience sample of 232 subjects with MS underwent RA, mainly examining item fit, reliability indices, test information function, dimensionality, local item independence, and differential item functioning (DIF). Most items fitted the Rasch model, but 13/88 items showed a misfit in infit and/or outfit values. Rasch reliability indices were high (> 0.80). Test information functions in most subscales showed a sharp decrease in measurement precision as the ability level departs from the quite limited central range of maximal information. The unidimensionality of each subscale was confirmed. Thirteen item pairs showed local dependency (residual correlations > 0.30) and three items presented DIF. Reliability, dimensionality and some internal construct validity characteristics of the MSSS-88-IT were confirmed. But, drawbacks of the original MSSS-88 emerged related to some item misfit, redundancy, or malfunctioning. Thus, further large independent studies are recommended, to verify the robustness of previous findings and examine the appropriateness of a few targeted item replacements.

Minimum Detectable Measurement Difference for Health-Related Quality of Life Measures Varies With Age and Disability in Adult Spinal Deformity: Implications for Calculating Minimal Clinically Important Difference.

Retrospective cohort. To investigate the minimum detectable measurement difference (MDMD) in the Scoliosis Research Society-22r (SRS-22r) outcomes instrument in adult spinal deformity (ASD) and to evaluate the effect of baseline data on measurable difference. The minimum clinically important difference (MCID) is the smallest, clinically relevant change observed and has been proposed for the SRS-22r instrument in ASD as 0.4. The MCID must be greater than the MDMD to be useful. The MDMD for the SRS-22r has not been calculated, nor have the effect of patient baseline values on MDMD. A prospective observation cohort was queried for patients treated both operatively and nonoperatively for ASD. Patients with baseline and 1-year, 2-year follow-up SRS-22r data were included in the analysis. The MDMD was calculated using classical test theory and item-response theory methods. Effect size and standardized response means were calculated. The effect of baseline data values was evaluated for MDMD. A total 839 Patients were eligible for cohort inclusion with 428 (51%) eligible for analysis with complete data. MDMD for Pain (0.6) and Self-Image (0.5) were greater than 0.4. MDMD varied with age (highest for the youngest patients) and with disability (highest for SF-36 Physical Component Summary <28.6). MDMD was less than 0.4 for Activity (0.3), Mental Health (0.3), and Total Score (0.2). Gender and mental health did not affect MDMD for the SRS-22r instrument. An MCID of 0.4 for the SRS-22r total score and domain scores may not be an appropriate value as the calculated MDMD is greater than 0.4 for both the Pain and Self-Image subscores. The MDMD for the SRS-22r instrument varied with age and baseline disability, making the assessment of clinically significant change more difficult using this tool. The MCID must be considered in the setting of the MDMD for instruments used to assess outcomes in ASD. 3.

What Is Bad From the Gander Is Bad From the Goose: Development and Validation of the Women's Objectification of Women Scale.

Existing measures of experiences of sexualization and objectification of women focus on behaviors that men do toward women. However, women may also contribute to the objectification of other women. The aim of the present study was to develop the Women's Objectification of Women Scale (WOWS). Through a series of four studies using samples of college women and samples obtained through MTurk, we (a) established that existing measures of objectification focus on behaviors that men perform, (b) gathered qualitative data on women's experiences of objectification by women, (c) developed models of the WOWS using classical test theory methods and item response theory, and (d) subjected the WOWS to confirmatory factor analysis and validity testing. The WOWS is a psychometrically sound, brief assessment of women's experiences of objectification by other women and may help further research on women's interpersonal experiences as they pertain to body image concerns, mental health, and well-being.

Development and validation of PediaTrac™: A web-based tool to track developing infants

ObjectivePediaTrac™, a 363-item web-based tool to track infant development, administered in modules of ∼40-items per sampling period, newborn (NB), 2­-, 4­-, 6­-, 9­- and 12­-months was validated. Caregivers answered demographic, medical, and environmental questions, and questions covering the sensorimotor, feeding/eating, sleep, speech/language, cognition, social-emotional, and attachment domains. MethodsExpert Panel Reviews and Cognitive Interviews (CI) were conducted to validate the item bank. Classical Test Theory (CTT) and Item Response Theory (IRT) methods were employed to examine the dimensionality and psychometric properties of PediaTrac with pooled longitudinal and cross-sectional cohorts (N = 132). ResultsIntraclass correlation coefficients (ICC) for the Expert Panel Review revealed moderate agreement at 6 ­months and good reliability at other sampling periods. ICC estimates for CI revealed moderate reliability regarding clarity of the items at NB and 4 months, good reliability at 2-­, 9­- and 12­-months and excellent reliability at 6 ­months. CTT revealed good coefficient alpha estimates (α ≥ 0.77 for five of the six ages) for the Social-Emotional/Communication, Attachment (α ≥ 0.89 for all ages), and Sensorimotor (α ≥ 0.75 at 6-months) domains, revealing the need for better targeting of sensorimotor items. IRT modeling revealed good reliability (r = 0.85–0.95) for three distinct domains (Feeding/Eating, Social-Emotional/Communication and Attachment) and four subdomains (Feeding Breast/Formula, Feeding Solid Food, Social-Emotional Information Processing, Communication/Cognition). Convergent and discriminant construct validity were demonstrated between our IRT-modeled domains and constructs derived from existing developmental, behavioral and caregiver measures. Our Attachment domain was significantly correlated with existing measures at the NB and 2-month periods, while the Social-Emotional/Communication domain was highly correlated with similar constructs at the 6-, 9- and 12-month periods. ConclusionPediaTrac has potential for producing novel and effective estimates of infant development via the Sensorimotor, Feeding/Eating, Social-Emotional/Communication and Attachment domains.

Development and early validation of a patient-reported outcome measure to assess sleep amongst people experiencing problems with alcohol or other drugs.

Study ObjectivesTo develop a patient-reported outcome measure to assess sleep amongst people experiencing problems with alcohol or other drugs.MethodsItem development included secondary analyses of qualitative interviews with drug or alcohol users in residential treatment, a review of validated sleep measures, focus groups with drug or alcohol users in residential treatment, and feedback from drug or alcohol users recruited from community and residential settings. An initial version of the measure was completed by 549 current and former drug or alcohol users (442 in person and 107 online). Analyses comprised classical test theory methods, exploratory and confirmatory factor analysis, measurement invariance assessment, and item response theory (IRT).ResultsThe initial measure (30 items) had good content and face validity and was named the Substance Use Sleep Scale (SUSS) by addiction service users. After seven items were removed due to low item-factor loadings, two factors were retained and labeled: “Mind and Body Sleep Problems” (14 items) and “Substance-Related Sleep Problems” (nine items). Measurement invariance was confirmed with respect to gender, age, and administration format. IRT (information) and classical test theory (internal consistency and stability) indicated measure reliability. Standard parametric and nonparametric techniques supported convergent and discriminant validity.ConclusionsSUSS is an easy-to-complete patient–reported outcome measure of sleep for people with drug or alcohol problems. It can be used by those concerned about their own sleep, and by treatment providers and researchers seeking to better understand, assess, and potentially treat sleep difficulties amongst this population. Further validity testing with larger and more diverse samples is now required.

An evaluation of the structural validity of the shoulder pain and disability index (SPADI) using the Rasch model.

The shoulder pain and disability index (SPADI) has been extensively evaluated for its psychometric properties using classical test theory (CTT). The purpose of this study was to evaluate its structural validity using Rasch model analysis. Responses to the SPADI from 1030 patients referred for physiotherapy with shoulder pain and enrolled in a prospective cohort study were available for Rasch model analysis. Overall fit, individual person and item fit, response format, dependence, unidimensionality, targeting, reliability and differential item functioning (DIF) were examined. The SPADI pain subscale initially demonstrated a misfit due to DIF by age and gender. After iterative analysis it showed good fit to the Rasch model with acceptable targeting and unidimensionality (overall fit Chi-square statistic 57.2, p = 0.1; mean item fit residual 0.19 (1.5) and mean person fit residual 0.44 (1.1); person separation index (PSI) of 0.83. The disability subscale however shows significant misfit due to uniform DIF even after iterative analyses were used to explore different solutions to the sources of misfit (overall fit (Chi-square statistic 57.2, p = 0.1); mean item fit residual 0.54 (1.26) and mean person fit residual 0.38 (1.0); PSI 0.84). Rasch Model analysis of the SPADI has identified some strengths and limitations not previously observed using CTT methods. The SPADI should be treated as two separate subscales. The SPADI is a widely used outcome measure in clinical practice and research; however, the scores derived from it must be interpreted with caution. The pain subscale fits the Rasch model expectations well. The disability subscale does not fit the Rasch model and its current format does not meet the criteria for true interval-level measurement required for use as a primary endpoint in clinical trials. Clinicians should therefore exercise caution when interpreting score changes on the disability subscale and attempt to compare their scores to age- and sex-stratified data.

Validation of the Brief Symptom Inventory-18 Among Low-Income African American Adolescents Exposed to Community Violence.

African American youth, especially those who reside in low resourced communities, are exposed to higher levels of exposure to community violence relative to their counterparts from other race/ethnic groups. However, appropriate measures for assessing psychological stress related to such exposures are underresearched in the extant literature for this population. The aim of the current study was to examine the reliability and validity of the Brief Symptom Inventory (BSI-18) scale among African American youth exposed to community violence through classical test theory and item response theory methods. Internal reliability and construct validity were examined. Results indicated good internal reliability (α = .93). Construct validity of the BSI-18 was established through confirmatory factor analysis with the three-factor somatic, depression, and anxiety model. Construct validity was also determined with all items indicating adequate fit. Our study indicates good reliability and validity of the BSI-18 to assess psychological distress among African American youth exposed to community violence.

Investigating the Impact of Missing Data Handling Methods on the Detection of Differential Item Functioning

In this study, it is aimed to investigate the impact of different missing data handling methods on the detection of Differential Item Functioning methods (Mantel Haenszel and Standardization methods based on Classical Test Theory and Likelihood Ratio Test method based on Item Response Theory). In this regard, on the data acquired from 1046 candidates who entered to Foreign National Student Exam (FNSE) held in year 2016 by Mersin University (MEU) and answered Basic Skills subtest, using different missing data handling methods, differential item functioning analyses with Mantel Haenszel, Standardization and Likelihood Ratio Test methods are performed. Basic Skills test consists of 80 multiple choice items. The items are all binary scored (1-0) items. Among the participants 523 are female and 523 are male. The findings showed that the number of items flagged as DIF has changed with the used missing data handling methods. The DIF detection methods based on Classical Test Theory are more consistent within themselves compared to DIF detection method based on Item Response Theory, whereas the used missing data handling methods differentiate the DIF detected items and this difference reaches a significant level for Mantel Haenszel method

The Virtual Care Climate Questionnaire: Development and Validation of a Questionnaire Measuring Perceived Support for Autonomy in a Virtual Care Setting.

BackgroundWeb-based health behavior change interventions may be more effective if they offer autonomy-supportive communication facilitating the internalization of motivation for health behavior change. Yet, at this moment no validated tools exist to assess user-perceived autonomy-support of such interventions.ObjectiveThe aim of this study was to develop and validate the virtual climate care questionnaire (VCCQ), a measure of perceived autonomy-support in a virtual care setting.MethodsItems were developed based on existing questionnaires and expert consultation and were pretested among experts and target populations. The virtual climate care questionnaire was administered in relation to Web-based interventions aimed at reducing consumption of alcohol (Study 1; N=230) or cannabis (Study 2; N=228). Item properties, structural validity, and reliability were examined with item-response and classical test theory methods, and convergent and divergent validity via correlations with relevant concepts.ResultsIn Study 1, 20 of 23 items formed a one-dimensional scale (alpha=.97; omega=.97; H=.66; mean 4.9 [SD 1.0]; range 1-7) that met the assumptions of monotonicity and invariant item ordering. In Study 2, 16 items fitted these criteria (alpha=.92; H=.45; omega=.93; mean 4.2 [SD 1.1]; range 1-7). Only 15 items remained in the questionnaire in both studies, thus we proceeded to the analyses of the questionnaire’s reliability and construct validity with a 15-item version of the virtual climate care questionnaire. Convergent validity of the resulting 15-item virtual climate care questionnaire was confirmed by positive associations with autonomous motivation (Study 1: r=.66, P<.001; Study 2: r=.37, P<.001) and perceived competence for reducing alcohol intake (Study 1: r=.52, P<.001). Divergent validity could only be confirmed by the nonsignificant association with perceived competence for learning (Study 2: r=.05, P=.48).ConclusionsThe virtual climate care questionnaire accurately assessed participants’ perceived autonomy-support offered by two Web-based health behavior change interventions. Overall, the scale showed the expected properties and relationships with relevant concepts, and the studies presented suggest this first version of the virtual climate care questionnaire to be reasonably valid and reliable. As a result, the current version may cautiously be used in future research and practice to measure perceived support for autonomy within a virtual care climate. Future research efforts are required that focus on further investigating the virtual climate care questionnaire's divergent validity, on determining the virtual climate care questionnaire’s validity and reliability when used in the context of Web-based interventions aimed at improving nonaddictive or other health behaviors, and on developing and validating a short form virtual climate care questionnaire.

Social Withdrawal Among Individuals Receiving Psychiatric Care: Derivation of a Scale Using Routine Clinical Assessment Data to Support Screening and Outcome Measurement.

Social withdrawal is a symptom experienced by individuals with an array of mental health conditions, particularly those with schizophrenia and mood disorders. Assessments of social withdrawal are often lengthy and may not be routinely integrated within the comprehensive clinical assessment of the individual. This study utilized item response and classical test theory methods to derive a Social Withdrawal Scale (SWS) using items embedded within a routine clinical assessment, the RAI-Mental Health (RAI-MH). Using data from 60,571 inpatients in Ontario, Canada, a common factor analysis identified seven items from the RAI-MH that measure social withdrawal. A graded response model found that six items had acceptable discrimination parameters: lack of motivation, reduced interaction, decreased energy, flat affect, anhedonia, and loss of interest. Summing these items, the SWS was found to have strong internal consistency (Cronbach's alpha=0.82) and showed a medium to large effect size (d=0.77) from admission to discharge. Fewer individuals with high SWS scores participated in social activity or reported having a confidant compared to those with lower scores. Since the RAI-MH is available across clinical subgroups in several jurisdictions, the SWS is a useful tool for screening, clinical decision support, and evaluation.

A Psychometric Analysis of the Italian Version of the eHealth Literacy Scale Using Item Response and Classical Test Theory Methods

BackgroundThe eHealth Literacy Scale (eHEALS) is a tool to assess consumers’ comfort and skills in using information technologies for health. Although evidence exists of reliability and construct validity of the scale, less agreement exists on structural validity.ObjectiveThe aim of this study was to validate the Italian version of the eHealth Literacy Scale (I-eHEALS) in a community sample with a focus on its structural validity, by applying psychometric techniques that account for item difficulty.MethodsTwo Web-based surveys were conducted among a total of 296 people living in the Italian-speaking region of Switzerland (Ticino). After examining the latent variables underlying the observed variables of the Italian scale via principal component analysis (PCA), fit indices for two alternative models were calculated using confirmatory factor analysis (CFA). The scale structure was examined via parametric and nonparametric item response theory (IRT) analyses accounting for differences between items regarding the proportion of answers indicating high ability. Convergent validity was assessed by correlations with theoretically related constructs.ResultsCFA showed a suboptimal model fit for both models. IRT analyses confirmed all items measure a single dimension as intended. Reliability and construct validity of the final scale were also confirmed. The contrasting results of factor analysis (FA) and IRT analyses highlight the importance of considering differences in item difficulty when examining health literacy scales.ConclusionsThe findings support the reliability and validity of the translated scale and its use for assessing Italian-speaking consumers’ eHealth literacy.

A comparison of reliability and precision of subscore reporting methods for a state English language proficiency assessment

K–12 English language proficiency tests that assess multiple content domains (e.g., listening, speaking, reading, writing) often have subsections based on these content domains; scores assigned to these subsections are commonly known as subscores. Testing programs face increasing customer demands for the reporting of subscores in addition to the total test scores in today’s accountability-oriented educational environment. Although reporting subscores can provide much-needed information for teachers, administrators, and students about proficiency in the test domains, one of the major drawbacks of subscore reporting includes their lower reliability as compared to the test as a whole. In addition, viewing language domains as if they were not interrelated, and reporting subscores without considering this relationship between domains, may be contradictory to the theory of language acquisition.This study explored several methods of assigning subscores to the four domains of a state English language proficiency test, including classical test theory (CTT)-based number correct, unidimensional item response theory (UIRT), augmented item response theory (A-IRT), and multidimensional item response theory (MIRT), and compared the reliability and precision of these different methods across language domains and grade bands. The first two methods assessed proficiency in the domains separately, without considering the relationship between domains; the last two methods took into consideration relationships between domains. The reliability and precision of the CTT and UIRT methods were similar and lower than those of A-IRT and MIRT for most domains and grade bands; MIRT was found to be the most reliable method. Policy implications and limitations of this study, as well as directions for further research, are discussed.

Development and validation of a self-efficacy scale for postoperative rehabilitation management of lung cancer patients.

The purpose of this study was to develop a Self-Efficacy Scale for Rehabilitation Management designed specifically for postoperative lung cancer patients (SESPRM-LC) and to evaluate its psychometric properties. Based on the concept of self-management of chronic disease, items were developed from literature review and semistructured interviews of 10 lung cancer patients and screened by expert consultation and pilot testing. Psychometric evaluation was done with 448 postoperative lung cancer patients recruited from 5 tertiary hospitals in Fuzhou, China, by incorporating classical test theory and item response theory methods. A 6-factor structure was illustrated by exploratory factor analysis and confirmed by confirmatory factor analysis, explaining 60.753% of the total variance. The SESPRM-LC achieved Cronbach's α of 0.694 to 0.893, 2-week test-retest reliability of 0.652 to 0.893, and marginal reliability of 0.565 to 0.934. The predictive and criterion validities were demonstrated by significant association with theoretically supported quality-of-life variables (r=0.211-0.392, P<.01), and General Perceived Self-efficacy Scale (r=0.465, P<.01), respectively. Item response theory analysis showed that the SESPRM-LC offers information about a broad range of self-efficacy measures and discriminates well between patients with high and low levels of self-efficacy. We demonstrated initial support for the reliability and validity of the 27-item SESPRM-LC, as a developmentally appropriate instrument for assessing self-efficacy among lung cancer patients during postoperative rehabilitation.

Humor as a Coping Strategy for People with Usher Syndrome

Introduction: Usher syndrome (USH) is a genetic condition characterized by hearing loss or deafness and progressive vision loss. Due to their dual sensory impairment, people with USH may have problems perceiving humor in their surroundings. The purpose of this study was to assess the sense and use of humor as a coping strategy in people with USH. Additionally, the differences between depressed and non-depressed people with USH were evaluated. Methods: Two questionnaires were used: The Coping Humor Scale (CHS) and the Sense of Humor Scale (SHS) each in the German version. The questionnaires were filled in by 86 persons with USH, primarily recruited from self-help groups (ages 27-75, mean age = 48; 48 % female; 9 % depressed). As comparison samples German people were used, on which the German edition were normed. Differences between the USH sample and the comparison sample were determined by using methods of classical test theory. Results: In comparison to a given control group, people with USH use less humor to cope with stress in difficult situations (p = .00). They are less playful and in a less positive mood (p = .02), laugh less (p = .02) and use less humor under stress (p = .00). Depressive persons with USH are more serious (p = .01) and less playful (p = .05) than the non-depressed group. Discussion: Overall the results indicate that people with USH may not use humor as a coping strategy. Thus there is a need for special programs such as Humor training and Laughter Yoga, which are based on the tactile sense, in order to develop beneficial coping strategies for people with USH. Such programs may help them to use and understand humor as a resource for stress management. Given this persons with USH and depression should be encouraged to actively engage in humorous situations with a positive mood.

Assessment of Burden Among Family Caregivers of People With Parkinson's Disease Using the Zarit Burden Interview

ContextPrevious studies have supported the psychometric properties of the 22-Item Zarit Burden Interview (ZBI-22) scale among family caregivers of people with various disorders, including Parkinson's disease (PD). However, its short forms have not been psychometrically tested among PD family caregivers, and available psychometric analyses have not accounted for the ordinal nature of item-level data. ObjectivesTo assess the psychometric properties of the ZBI-22 and its short forms among family caregivers of people with PD, while taking account for the ordinal nature of data. MethodsCross-sectional postal survey ZBI-22 data from 66 family caregiver members (59% women; mean age 69.6 years) of a local Swedish PD society branch were analyzed according to classical test theory methods based on polychoric/polyserial correlations. ResultsMissing item responses were ≤ 5%. Corrected item-total correlations were ≥ 0.42 and floor/ceiling effects were <20%, besides for the briefest (4- and 1-item) short forms (20% and 40% floor effects, respectively). Reliability was good for all scales (ordinal alpha 0.89–0.95). External construct validity was in general accordance with a priori expectations. Short forms demonstrated good criterion-related validity (rs 0.87–0.99) and discriminative ability (area under the curve, 0.91–0.98) relative to the full ZBI-22. ConclusionThis study provides support for the reliability and validity of the ZBI-22 and its various short forms for use among PD family caregivers. In studies where caregiver burden is a central outcome, either ZBI-22 or ZBI-12 is suggested for use; other short forms can be used when caregiver burden is of less central focus or for clinical screening.

Comparison of Classical Test Theory and Item Response Theory in Individual Change Assessment.

Clinical psychologists are advised to assess clinical and statistical significance when assessing change in individual patients. Individual change assessment can be conducted using either the methodologies of classical test theory (CTT) or item response theory (IRT). Researchers have been optimistic about the possible advantages of using IRT rather than CTT in change assessment. However, little empirical evidence is available to support the alleged superiority of IRT in the context of individual change assessment. In this study, the authors compared the CTT and IRT methods with respect to their Type I error and detection rates. Preliminary results revealed that IRT is indeed superior to CTT in individual change detection, provided that the tests consist of at least 20 items. For shorter tests, however, CTT is generally better at correctly detecting change in individuals. The results and their implications are discussed.

Rasch analysis of the Italian Lower Extremity Functional Scale: insights on dimensionality and suggestions for an improved 15-item version

Objective: To investigate dimensionality and the measurement properties of the Italian Lower Extremity Functional Scale using both classical test theory and Rasch analysis methods, and to provide insights for an improved version of the questionnaire. Design: Rasch analysis of individual patient data. Setting: Rehabilitation centre. Participants: A total of 135 patients with musculoskeletal diseases of the lower limb. Results: Patients were assessed with the Lower Extremity Functional Scale before and after the rehabilitation. Rasch analysis showed some problems related to rating scale category functioning, items fit, and items redundancy. After an iterative process, which resulted in the reduction of rating scale categories from 5 to 4, and in the deletion of 5 items, the psychometric properties of the Italian Lower Extremity Functional Scale improved. The retained 15 items with a 4-level response format fitted the Rasch model (internal construct validity), and demonstrated unidimensionality and good reliability indices (person-separation reliability 0.92; Cronbach’s alpha 0.94). Then, the analysis showed differential item functioning for six of the retained items. The sensitivity to change of the Italian 15-item Lower Extremity Functional Scale was nearly equal to the one of the original version (effect size: 0.93 and 0.98; standardized response mean: 1.20 and 1.28, respectively for the 15-item and 20-item versions). Conclusion: The Italian Lower Extremity Functional Scale had unsatisfactory measurement properties. However, removing five items and simplifying the scoring from 5 to 4 levels resulted in a more valid measure with good reliability and sensitivity to change.

The Mini-BESTest: a review of psychometric properties.

The Mini-Balance Evaluation Systems Test (Mini-BESTest) has been identified as the most comprehensive balance measure for community-dwelling adults and elderly individuals. It can be used to assess balance impairments in several other conditions, mainly Parkinson's disease and stroke. Despite increasing use of the Mini-BESTest since it was first published 5 years ago, no systematic review synthesizing its psychometric properties is available. The aim of this study was to provide a comprehensive review of the psychometric properties of the Mini-BESTest when administered to patients with balance deficits because of different diseases. A literature search was performed on articles published before July 2015 in journals indexed by MEDLINE and Scopus databases. The search produced 98 papers, 24 of which fulfilled the inclusion criteria for this review. Most papers (n=19) focused on patients affected by neurological diseases, mainly Parkinson's disease. In 21 papers, the psychometric characteristics were analyzed using Classical Test Theory methods and in only three papers was Rasch analysis carried out. This review shows the interest of researchers in the Mini-BESTest despite the short time frame since its first publication. The Mini-BESTest is used widely in both clinical practice and research. The results support the reliability, validity, and responsiveness of this instrument and it can be considered a standard balance measure. However, it would be valuable to learn more about how this scale performs in different diseases causing balance deficits and to better define the minimal clinically important difference for each disease.