Methodological considerations in cross-sectional studies validating the International Classification of Functioning, Disability and Health (ICF) Core-Sets: a systematic review.

The quality of cross-sectional studies validating ICF-CSs was satisfactory, although several articles did not describe aspects such as sample size calculation. Validity evidence for ICF-CS studies could be improved by conducting more multicenter studies, replicating ICF-CS validation studies in different WHO regions, and through synthesis of existing research.