Optimizing the design of visual analogue scales for assessing quality of life: a semi-qualitative study among Chinese-speaking Singaporeans

Objectives Current recommendations for visual analogue scale (VAS) design are largely derived from studies on pain assessment. We evaluated respondent preferences for VAS design for health‐related quality of life (HRQoL) assessment. Methods In‐depth interviews were conducted among Chinese‐speaking rheumatology outpatients and caregivers (age ≥ 21 years) to determine preferences for the following: (1) VAS orientation (horizontal/vertical); (2) length of instructions (long/intermediate/short); (3) scale range (0–10/0–100 points); (4) indicator for computerized touchscreen VAS (bar/column). Responses in subjects expressing a preference were compared using tests of proportions. Results Among 101 subjects, more subjects preferred a horizontal over a vertical format (48 vs. 37, P = 0.23; 16 no preference), and intermediate length over long/short instructions (44 vs. 14 vs. 31, P = 0.004; 12 no preference). A scale range of 0–10 was preferred over 0–100 (62 vs. 21, P < 0.001; 18 no preference). A bar indicator was preferred over a column for computerized touchscreen VAS (54 vs. 44, P = 0.31; 3 no preference). Only presence of chronic medical conditions influenced subject preference odds ratio (95% confidence interval): 3.9 (1.6–9.6), P = 0.002]. Conclusion Chinese‐speaking subjects preferred a 0–10‐point VAS with intermediate length instructions for HRQoL assessment. Thus, a 0–10‐point VAS with intermediate length instructions may be more useful for HRQoL assessment among Chinese subjects.