title: Validation of a Chinese version of the Cardiff Acne Disability Index.
abstract: OBJECTIVE
  To assess the validity (face validity and criterion-related validity) and reliability (test-retest reliability and internal consistency) of a Cantonese (the Chinese dialect predominantly used in Guangdong Province) version of the Cardiff Acne Disability Index.
  
  
  METHODS
  Questionnaire study.
  
  
  METHODS
  Two secondary schools in Hong Kong.
  
  
  METHODS
  The Chinese Cardiff Acne Disability Index was translated according to international guidelines including forward-backward translation, reconciliation, and cognitive debriefing. A questionnaire, which was composed of the resultant Chinese Cardiff Acne Disability Index and the Cantonese Dermatology Life Quality Index (for those aged more than 16 years) or the Cantonese Children's Dermatology Life Quality Index (for those aged 16 years or less) was administered to 85 eligible secondary school students.
  
  
  METHODS
  Establishing face validity, criterion-related validity, internal consistency, and test-retest reliability by standard testing.
  
  
  RESULTS
  The face validity was satisfactory. The strength of the relationship between the Chinese Cardiff Acne Disability Index and Dermatology Life Quality Index was large (gammas=0.58) and significant (P=0.004). The strength of relationship between the Chinese Cardiff Acne Disability Index and Cantonese Dermatology Life Quality Index was also large (gammas=0.72) and significant (P<0.001). Regarding internal consistency, Cronbach's alpha was 0.763. Thirty-three students completed the test-retest reliability test, and the resulting correlation of the first and second administration of the Chinese Cardiff Acne Disability Index was strong (gammas=0.795, P<0.001). The intra-class correlation coefficient was satisfactory (0.784, P<0.001).
  
  
  CONCLUSIONS
  The Chinese Cardiff Acne Disability Index was equivalent to the original English version, and constitutes a valid and reliable tool for day-to-day clinical use.
authors.affiliation: Department of Community and Family Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. pmlaw@cuhk.edu.hk
authors.forename: Michelle P M
authors.initials: MP
authors.lastname: Law
authors.forename: Antonio A T
authors.initials: AA
authors.lastname: Chuh
authors.forename: Albert
authors.initials: A
authors.lastname: Lee
mesh_terms: D000152:Acne Vulgaris / Q000523:psychology*; D000293:Adolescent; D044466:Asian People; D004185:Disability Evaluation; D005260:Female; D006723:Hong Kong; D006801:Humans; D008297:Male; D012574:Schools; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires / Q000592:standards*; D014175:Translating; D055815:Young Adult