Optimizing the design of visual analogue scales for assessing quality of life: a semi-qualitative study among Chinese-speaking Singaporeans.
OBJECTIVE
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 > or = 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].


CONCLUSIONS
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.
Wee
Hwee-Lin
HL
Department of Rheumatology and Immunology, Singapore General Hospital, and Deparment of Pharmacy, National University of Singapore, Singapore.
Fong
Kok-Yong
KY
Tse
Connie
C
Machin
David
D
Cheung
Yin-Bun
YB
Luo
Nan
N
Thumboo
Julian
J
D000328:Adult; D002681:China / Q000208:ethnology; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D012846:Singapore