Quality of Life General (QGEN^®) Survey

Quality of Life General (QGEN^®) is a new patient-reported outcome (PRO) survey published by JWRG to improve single-item-per-domain (SIPD) estimates of the eight most frequently measured health-related quality of life (HRQOL) domains, including: functioning (physical, role, and social) and feelings (pain, vitality, and mental health). QGEN items improve Medical Outcomes Study (MOS) short forms (SF) by increasing response category ranges for all functioning domains enough to raise the “ceiling” by about 1.0 SD units. This is accomplished by redefining the most favorable response as “Easy to do” in place of the legacy “Not at all limited” category. Other new QGEN bipolar items each directly measure both of the opposite poles for a higher order feeling domain, including Mental Health (psychological distress vs well-being) and Vitality (feeling energetic vs. worn out). Historically, these advantages of greater breadth and range could only be achieved with multi-item measures for each domain. The result is improved overall item efficiency (information/item) and increased score range enough to significantly reduce ceiling effects, while maintaining convergent and discriminant validity in comparison with the best legacy items and multi-item scales for the miost frequently meaured domains.

With standardized norm-based scoring, QGEN items also provide unbiased estimates of average scores for the profile of MOS multi-item scales for the same eight domains and accurately estimate SF-36 physical (PCS) and mental (MCS) summary scores and the SF-6D health utility index in general and chronically ill US populations. As with all MOS short forms, higher scores indicate better health related functioning and well-being. Specifically, all scores are transformed to have mean=50 and SD=10 in a true probability sample representing 97% of the general US population surveyed by NORC. This standardization enables meaningful comparisons with more than three decades of published population norms, effect sizes, minimally important differences, and other proven interpretation guidelines.

A key practical advantage of QGEN is its efficiency. In comparison with SF-36 and comparable (e.g., PROMIS) multi-item short-forms measuring the same domains, the eight-item QGEN reduces survey administration time by more than 75%, to about 1 minute for most respondents while increasing score range and broadening domain representation. This makes it a convenient and efficient option for maintaining comparability with the metrics most widely in clinical and general population studies of QOL outcomes.

JWRG’s objective is to increase the efficiency of single-item-per-domain (SIPD) health-related quality of life (QOL) measurement enough to enable representation of essential QOL domains in general population and clinical surveys that have severe respondent burden constraints.