[Interrater reliability of instruments for the evaluation of needs of bedridden persons: a review of the international literature].

Objective and reliable rating of disability and functional dependence is of utmost importance for both medical and rehabilitation research and the practice of social medicine. The present paper provides an overview on internationally used disability scales and on studies that were carried out to determine their inter-rater reliability. Most of the scales were developed in the United States. The number and quality of inter-rater reliability studies strongly vary for various scales. In general, reliability was found to be high for summary scores of disability, whereas reliability strongly varied from extremely poor to excellent for single items of disability. This variation provides valuable suggestions for improving rating of disability.