Dataset Information

Methodological issues regarding power of classical test theory (CTT) and item response theory (IRT)-based approaches for the comparison of patient-reported outcomes in two groups of patients--a simulation study.

ABSTRACT:

Background

Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statistical properties of CTT and IRT, regarding power and corresponding effect sizes, were compared.

Methods

Two-group cross-sectional studies were simulated for the comparison of PRO data using IRT or CTT-based analysis. For IRT, different scenarios were investigated according to whether items or person parameters were assumed to be known, to a certain extent for item parameters, from good to poor precision, or unknown and therefore had to be estimated. The powers obtained with IRT or CTT were compared and parameters having the strongest impact on them were identified.

Results

When person parameters were assumed to be unknown and items parameters to be either known or not, the power achieved using IRT or CTT were similar and always lower than the expected power using the well-known sample size formula for normally distributed endpoints. The number of items had a substantial impact on power for both methods.

Conclusion

Without any missing data, IRT and CTT seem to provide comparable power. The classical sample size formula for CTT seems to be adequate under some conditions but is not appropriate for IRT. In IRT, it seems important to take account of the number of items to obtain an accurate formula.

SUBMITTER: Sebille V

PROVIDER: S-EPMC2858729 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Methodological issues regarding power of classical test theory (CTT) and item response theory (IRT)-based approaches for the comparison of patient-reported outcomes in two groups of patients--a simulation study.

Sébille Véronique V Hardouin Jean-Benoit JB Le Néel Tanguy T Kubis Gildas G Boyer François F Guillemin Francis F Falissard Bruno B

BMC medical research methodology 20100325

<h4>Background</h4>Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statistical properties of CTT and IRT, regarding power and corresponding effect sizes, were compared. ...[more]

PMID: 20338031

Similar Datasets

Project description:BackgroundThe International Classification of Functioning, Disability and Health (ICF) proposes three main health outcomes, Impairment (I), Activity Limitation (A) and Participation Restriction (P), but good measures of these constructs are needed The aim of this study was to use both Classical Test Theory (CTT) and Item Response Theory (IRT) methods to carry out an item analysis to improve measurement of these three components in patients having joint replacement surgery mainly for osteoarthritis (OA).MethodsA geographical cohort of patients about to undergo lower limb joint replacement was invited to participate. Five hundred and twenty four patients completed ICF items that had been previously identified as measuring only a single ICF construct in patients with osteoarthritis. There were 13 I, 26 A and 20 P items. The SF-36 was used to explore the construct validity of the resultant I, A and P measures. The CTT and IRT analyses were run separately to identify items for inclusion or exclusion in the measurement of each construct. The results from both analyses were compared and contrasted.ResultsOverall, the item analysis resulted in the removal of 4 I items, 9 A items and 11 P items. CTT and IRT identified the same 14 items for removal, with CTT additionally excluding 3 items, and IRT a further 7 items. In a preliminary exploration of reliability and validity, the new measures appeared acceptable.ConclusionNew measures were developed that reflect the ICF components of Impairment, Activity Limitation and Participation Restriction for patients with advanced arthritis. The resulting Aberdeen IAP measures (Ab-IAP) comprising I (Ab-I, 9 items), A (Ab-A, 17 items), and P (Ab-P, 9 items) met the criteria of conventional psychometric (CTT) analyses and the additional criteria (information and discrimination) of IRT. The use of both methods was more informative than the use of only one of these methods. Thus combining CTT and IRT appears to be a valuable tool in the development of measures.

Project description:BackgroundThe Health of the Nation Outcome Scale (HoNOS) is a widely used 12-item tool to assess mental health and social functioning. The French version has an added 13th item measuring adherence to psychotropic medication. The aim of the current study is to uncover the unknown pattern of the new item 13 and to compare the unidimensional and multidimensional fit of the new HoNOS-13 using Item Response Theory (IRT). This research question was studied among inpatients with substance use disorder (SUD).MethodsSix hundred and nine valid questionnaires of HoNOS-13 were analyzed using unidimensional (one-factor) and multidimensional (two-factor) IRT modeling.ResultsThe multidimensional model suggesting a first factor capturing psychiatric/impairment-related issues and a second factor reflecting social-related issues yielded better goodness-of-fit values compared to the unidimensional solution. This resulted in an improvement of all slope parameters which in turn translates to better discriminative power. Significant improvement in item location parameters were observed as well. The new item 13 had a good discriminative power (1.17) and covered a wide range of the latent trait (- 0.14 to 2.64).ConclusionsWe were able to validate the 13-item questionnaire including medication compliance and suggest that the HoNOS-13 can be recommended as a clinical evaluation tool to assess the problems and treatment needs for inpatients with SUD. Interestingly, the majority of item response categories are endorsed by respondents who are below and above the average levels of HoNOS. This indicates that the scale is able to discriminate between participants both at the low and at the high ends of the latent trait continuum. More importantly, the new item 13 has a good discriminative power and covers a broad range of the latent trait below and above the mean. It therefore has the desired profile of a good item and is a useful measure for the assessment of mental health and social functioning. Trial registration ClinicalTrials.gov, Identifier: NCT03551301. Registered: 11.06.2018. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03551301 .

Project description:PURPOSE:The association of chronic lymphocytic leukemia (CLL) with health-related quality of life (HRQoL) is rarely studied globally. This study evaluated the psychometric properties of the EORTC-Chronic Lymphocytic Leukaemia (CLL17 [phase III]) module, a newly developed assessment on CLL patients' HRQoL, among Chinese CLL patients. METHODS:The Chinese CLL17, comprised of three subscales (symptom burden [SB], physical condition [PC] and worries/fears [WF]), was provided by the developer team through EORTC. A cross-sectional online survey was conducted to collect data. The classical traditional theory (CTT) and the item response theory (IRT) were used to evaluate the psychometric properties of CLL17. Internal consistency reliability was determined by the Cronbach's alpha and item-total correlation. Dimensionality was verified through confirmatory factor analysis (CFA). Convergent validity was also assessed. The generalized partial credit model was used for the IRT. The difficulty, discrimination, item fit, and differential item functioning (DIF) were calculated to assess the instrument's psychometric properties. RESULTS:In all, 318 patients, aged between 26 and 82 years, completed the questionnaire. A good level of internal reliability was achieved (Cronbach's alpha = 0.92). The item-total correlation coefficient ranged from 0.46 to 0.72. There was a mid-to-high correlation between CLL17 and domains of EQ-5D and QLQ-C30. The IRT model showed a satisfactory homogeneity, item fit and good discrimination of items, except for item 4, 6 and 16 (< 1.0). low information provided by item 16 and 17. SB and PC provided more information with theta > 0, whereas WF provided more information with theta < 0. Item 17 perform inconsistently for respondents from different age groups (DIF). CONCLUSION:The EORTC-CLL17 Chinese version shows acceptable reliability and validity, making it a valuable instrument to evaluate the impact on the HRQoL of Chinese CLL patients.

Dataset Information

Methodological issues regarding power of classical test theory (CTT) and item response theory (IRT)-based approaches for the comparison of patient-reported outcomes in two groups of patients--a simulation study.

Background

Methods

Results

Conclusion

Publications

Methodological issues regarding power of classical test theory (CTT) and item response theory (IRT)-based approaches for the comparison of patient-reported outcomes in two groups of patients--a simulation study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets