OBJECTIVE: To explore internal consistency and correlations between perceived ability, performance and perceived importance in a preliminary selection of self-reported items representing the activity/participation component of the International Classification of Functioning, Disability and Health (ICF).

DESIGN: Structured interview study.

SUBJECTS: Fifty-five Swedish adolescents and adults with a mild intellectual disability.

METHODS: Questions about perceived ability, performance and perceived importance were asked on the basis of a 3-grade Likert-scale regarding each of 68 items representing the 9 ICF domains of activity/participation.

RESULTS: Internal consistency for perceived ability (Cronbach’s alpha for all 68 items): 0.95 (values for each domain varied between 0.57 and 0.85), for performance: 0.86 (between 0.27 and 0.66), for perceived importance: 0.84 (between 0.27 and 0.68). Seventy-two percent of the items showed correlations > 0.5 (mean = 0.59) for performance vs perceived importance, 41% > 0.5 (mean = 0.47) for perceived ability vs performance and 12% > 0.5 (mean = 0.28) for perceived ability vs perceived importance.

CONCLUSION: Measures of performance and perceived importance may have to be based primarily on their estimated clinical relevance for describing aspects of the ICF participation concept. With a clinimetric approach, parts of the studied items and domains may be used to investigate factors related to different patterns and levels of participation, and outcomes of rehabilitation.