Jonathan L. Nazari, AS Pickard, Justin Yu, Maja Kuharić
BACKGROUND: The EQ-HWB-9 is a measure designed to capture health, social care, and caregiver-related quality of life across relevant populations. As part of ongoing development, modifications have been made to item wording, response scales, and layout informed by international collaborations. Qualitative evidence to support the content validity of the modified EQ-HWB-9 in the United States (US) is important to support its use in this major market. This study evaluated the comprehensibility, relevance, and comprehensiveness of the modified EQ-HWB-9 in US adults. METHODS: US adults with chronic health conditions, serving as unpaid caregivers, and/or social care users were purposively recruited through an online panel. Participants independently completed an online, pre-interview survey including both experimental and modified EQ-HWB-9 versions and a cognitive interview conducted online using a semi-structured interview guide. Participants compared experimental and modified wording, response scales, layout, provided item-level interpretations and examples, and discussed perceived comprehensiveness of the measure. Interviews were conducted until thematic saturation was achieved. Verbatim transcripts were qualitatively coded and analyzed using the framework method. RESULTS: Thirty-four participants (mean age 55; 71% female) completed interviews. Most items demonstrated strong face and content validity; participants readily interpreted daily activities, exhaustion, loneliness, anxiety, sadness/depression, and pain as intended and provided rich, relevant examples. However, the mobility item was identified by several participants as applying only to users of mobility devices. Across modifications, participants preferred "difficulty" over "trouble" (cognition), "lack of control" over "no control," "a little of the time" over "only occasionally," and "moderate difficulty" over "some difficulty." Most participants found repeated question stems clearer than shared item stems. Half of respondents perceived the EQ-HWB-9 as comprehensive, with suggested additions (e.g., sleep, self-care) largely aligning with domains included in the long-form EQ-HWB. CONCLUSIONS: Findings provide qualitative support for the content validity of the modified EQ-HWB-9 in US populations and reinforce several proposed wording and response-scale refinements. Select issues identified with the wording of the mobility and control items can inform revisions in the wording of a finalized version of the EQ-HWB.