Developing item banks to measure three important domains of health-related quality of life (HRQOL) in Singapore

Abstract

Objectives: To develop separate item banks for three health domains of health-related quality of life (HRQOL) ranked as important by Singaporeans - physical functioning, social relationships, and positive mindset. Methods: We adapted the Patient Reported Outcomes Measurement Information System Qualitative Item Review protocol, with input and endorsement from laymen and experts from various relevant fields. Items were generated from 3 sources: 1) thematic analysis of focus groups and in-depth interviews for framework (n = 134 participants) and item(n = 52 participants) development, 2) instruments identified from a literature search (PubMed) of studies that developed or validated a HRQOL instrument among adults in Singapore, 3) a priori identified instruments of particular relevance. Items from these three sources were "binned" and "winnowed" by two independent reviewers, blinded to the source of the items, who harmonized their selections to generate a list of candidate items (each item representing a subdomain). Panels with lay and expert representation, convened separately for each domain, reviewed the face and content validity of these candidate items and provided inputs for item revision. The revised items were further refined in cognitive interviews. Results: Items from our qualitative studies (51 physical functioning, 44 social relationships, and 38 positive mindset), the literature review (36 instruments from 161 citations), and three a priori identified instruments, underwent binning, winnowing, expert panel review, and cognitive interview. This resulted in 160 candidate items (61 physical functioning, 51 social relationships, and 48 positive mindset). Conclusions: We developed item banks for three important health domains in Singapore using inputs from potential end-users and the published literature. The next steps are to calibrate the item banks, develop computerized adaptive tests (CATs) using the calibrated items, and evaluate the validity of test scores when these item banks are administered adaptively.