title: Optimizing the design of visual analogue scales for assessing quality of life: a semi-qualitative study among Chinese-speaking Singaporeans.
abstract: 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.
authors.affiliation: Department of Rheumatology and Immunology, Singapore General Hospital, and Deparment of Pharmacy, National University of Singapore, Singapore.
authors.forename: Hwee-Lin
authors.initials: HL
authors.lastname: Wee
authors.forename: Kok-Yong
authors.initials: KY
authors.lastname: Fong
authors.forename: Connie
authors.initials: C
authors.lastname: Tse
authors.forename: David
authors.initials: D
authors.lastname: Machin
authors.forename: Yin-Bun
authors.initials: YB
authors.lastname: Cheung
authors.forename: Nan
authors.initials: N
authors.lastname: Luo
authors.forename: Julian
authors.initials: J
authors.lastname: Thumboo
mesh_terms: 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