Electrical Stimulus, Reentry, Fibrillation, and Defibrillation: Insights Gained by the Graded Response and Restitution Hypotheses

Objective The SNOT-22 (22-item Sinonasal Outcome Test) is a high-quality outcome measure that assesses chronic rhinosinusitis–specific quality of life. The aim of this study was to gain greater insight into the information provided by the SNOT-22 by determining its item-based psychometric properties. Study Design Retrospective cohort study. Setting Tertiary care academic centers. Methods This study used a previously described data set of the SNOT-22 completed by 800 patients with chronic rhinosinusitis. Item response theory graded response models were used to determine parameters reflecting item discrimination, difficulty, and information provided by each item toward the SNOT-22 subdomain to which it belonged. Results The unconstrained graded response model fitted the SNOT-22 data best. Item discrimination parameters and total information provided showed the greatest variability within the nasal subdomain, and the item related to sense of smell/taste demonstrated the lowest discrimination and provided the least amount of information overall. The dizziness item provided disparately lower total information and discrimination in the otologic/facial pain subdomain. Items in the sleep and emotional subdomains generally provided high discrimination. While items in the nasal, sleep, and otologic/facial pain subdomains spanned all levels of difficulty, emotional subdomain items covered higher levels of difficulty, indicating greater information provided at higher levels of disease severity. Conclusion The item-specific psychometric properties of the SNOT-22 support it as a high-quality instrument. Our results suggest the need and possibility for revision of the smell/taste dysfunction item, for example its wording, to improve its ability to discriminate among the different levels of disease burden.

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A Multidimensional Item Response Theory Model for Continuous and Graded Responses With Error in Persons and Items

Educational and Psychological Measurement ◽

10.1177/0013164421998412 ◽

2021 ◽

pp. 001316442199841

Author(s):

Pere J. Ferrando ◽

David Navarro-González

Keyword(s):

Item Response Theory ◽

Item Response ◽

Theory Model ◽

Response Model ◽

Response Theory ◽

Continuous Response ◽

Graded Responses ◽

Graded Response ◽

Continuous Responses ◽

Differential Measurement Error

Item response theory “dual” models (DMs) in which both items and individuals are viewed as sources of differential measurement error so far have been proposed only for unidimensional measures. This article proposes two multidimensional extensions of existing DMs: the M-DTCRM (dual Thurstonian continuous response model), intended for (approximately) continuous responses, and the M-DTGRM (dual Thurstonian graded response model), intended for ordered-categorical responses (including binary). A rationale for the extension to the multiple-content-dimensions case, which is based on the concept of the multidimensional location index, is first proposed and discussed. Then, the models are described using both the factor-analytic and the item response theory parameterizations. Procedures for (a) calibrating the items, (b) scoring individuals, (c) assessing model appropriateness, and (d) assessing measurement precision are finally discussed. The simulation results suggest that the proposal is quite feasible, and an illustrative example based on personality data is also provided. The proposals are submitted to be of particular interest for the case of multidimensional questionnaires in which the number of items per scale would not be enough for arriving at stable estimates if the existing unidimensional DMs were fitted on a separate-scale basis.

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