Grant: Travel Awards - Institute Community Support

Aims: Preference-based instruments are a quantitative measure of health-related quality of life (HRQoL) which can incorporate individual preferences to inform clinical and policy decisions. Condition-specific preference-based instruments (CSPBI) are more sensitive to clinical change. Creating a CSPBI from scratch first requires a health status classification system (MAS). There is no accepted algorithm to systematically create a MAS combining classical and modern measurement approaches: Rasch and item response theory. Methods: We conducted a systematic literature search in established medical literature databases. We supplemented a 2015 systematic review with additional concepts: IRT, Rasch analysis, HRQoL, and development of novel preference-based instruments. Two reviewers independently reviewed articles for inclusion and exclusion criteria. An algorithm was constructed based on literature analysis and expert consensus. Results: Goodwin found 51 disease-specific preference-based instruments, including 18 evaluated using Rasch analysis. From 2015 to 04-2017, 3162 articles met inclusion and exclusion criteria. Titles, abstracts, and full text were reviewed: 3 articles used Rasch and 1 used IRT analysis. An algorithm outlining critical decisions has seven main steps. 1) Investigators determine a domain structure. Qualitative approaches 2) create new items, and 3) reduce items based on impact. CTT is used to 4) test the domain structure. Either a Rasch or IRT approach is chosen in advance, and 5) tested for appropriateness, and used to select one item per domain 6) if needed, reduce item levels. CTT is also used to 5) select one item per domain, and 7) test measurement properties: reliability, validity, and responsiveness. Conclusions: This algorithm outlines a novel process for developing a MAS, combining IRT, Rasch, and CTT approaches. This can be applied to create a CSPBI responsive to clinically significant changes.