BACKGROUND: The CLEFT-Q, a questionnaire developed and validated specifically for cleft patients, contains 7 'appearance' scales. The ICHOM (International Consortium of Health Outcomes Measurement) has incorporated only some Cleft-Q 'appearance' scales in the Standard Set to minimize burden. This study evaluates which 'appearance' scales provide the most meaningful information in the different cleft types at specific ages, for the most efficient cleft appearance outcome assessment. METHODS: Within this international multicentre study, outcomes of the 7 appearance scales were collected, either as part of the ICHOM Standard Set, or as part of the field test study performed to validate the CLEFT-Q. Analyses were done in separate age-groups and cleft types, and involved univariate regression analyses, trend analyses, T-tests, correlations, and floor and ceiling effects. RESULTS: A total of 3116 patients were included. Scores for most appearance scales showed a downward trend by age-groups, with the exception of the Teeth and Jaw scales. In all cleft types, several scales correlated strongly with each other. No floor effects were observed, but ceiling effects were found in several scales in different age-groups, most often in the CLEFT-Q Jaw. CONCLUSION: A proposition for the most meaningful and efficient appearance outcome assessment in cleft patients is made. It was composed so that recommendations are of value for different cleft protocols and initiatives. Suggestions for the use of scales in the ICHOM Standard Set at different ages are given, also from a clinical perspective. Use of the CLEFT-Q Scar, Lips, and Nose, will provide additional relevant information.