Development of criteria for the qualifiers of activity and participation in the 'International Classification of Functioning, Disability and Health' based on the accumulated data of population surveys.

One of the purposes of this study is to describe the details and rationale of the criteria for qualifiers of the activity and participation of the International Classification of Functioning, Disability and Health that were developed based on population surveys and adopted provisionally by the International Classification of Functioning, Disability and Health Committee, Statistics Commission of Social Security Council of Japan in March 2007. The most important aspect of the criteria is the division of 'independence' of the activity into two different levels of 'Universal independence' (Qualifier 0) and 'Limited independence' (Qualifier 1) and the corresponding division of 'Full participation' (Qualifier 0) and 'Partial participation' (Qualifier 1) in the participation. These divisions reflect the paradigm shift in the basic concept of classification and evaluation of functioning and disability from 'only about people with disabilities' to 'about all people'. Another purpose is to present and analyze the accumulated data of population surveys on functioning in 17600 older people (aged 65 years and older) living in five different communities throughout Japan as the supporting evidence for the criteria. The analysis of these data offers good support for the relevance and usefulness of the criteria, especially in that the proposed division of Qualifier 0 ('Universal independence' and 'Full participation') and Qualifier 1 ('Limited independent and 'partial participation') is a very sensitive tool in the detection of milder problems in the activity and participation.