Questionnaire development: Face validity and item impact testing of the child oral health impact profile

Objective: The Child Oral Health Impact Profile (COHIP) was designed to assess oral-facial well-being in school-age children as reported by the child and via proxy report from a caregiver. This article describes the development of the COHIP using a multi-staged impact approach recommended by Guyatt et al. (Quality of life and pharmacoeconomics in clinical trials. Philadelphia, PA: Lippincott-Raven; 1996. p. 41). Methods: There were multiple phases to the development of the questionnaire: (i) initial pool of items developed from the literature and expert review; (ii) face validity of items; (iii) impact evaluation of the initial item pool; (iv) development of positive items and face validity of new items; (v) impact evaluation of the revised questionnaire and (vi) factor analysis and final revision of the questionnaire. Factor analysis was completed on the final questionnaire using data from the impact evaluation in order to evaluate whether the COHIP measured independent conceptual domains. Results: Factor analysis identified five domains: oral health, functional well-being, social/emotional well-being, school environment and self-image. Readability was calculated using the Flesch-Kinkaid readability score that was finalized at a 3.5 grade reading level. Finally, two response sets, and a revised format (e.g., including pictures, increasing font size, and shading every other item) were implemented to decrease respondent fatigue and increase accuracy of participant responses. Conclusions: The final questionnaire consisted of 34 items and five conceptually distinct subscales: oral health, functional well-being, social/emotional well-being, school environment and self-image. Subsequent papers present the validity and reliability of the COHIP.