ICF linking rules: an update based on lessons learned.

OBJECTIVE: Outcome research seeks to understand the end results of health services. Researchers use a wide variety of outcome measures including technical, clinical and patient-oriented measures. The International Classification of Functioning, Disability and Health (ICF) as a common reference framework for functioning may contribute to improved outcome research. The objective of this paper is to provide an updated version of the linking rules published in 2002 and illustrate how these rules are applied to link technical and clinical measures, health-status measures and interventions to the ICF. RESULTS: Three specific linking rules have been established to link health-status measures to the ICF and one specific linking rule has been created to link technical and clinical measures and interventions. A total of 8 linking rules have been established for use with all different outcome measures and with interventions. CONCLUSION: The newly updated linking rules will allow researchers systematically to link and compare meaningful concepts contained in them. This should prove extremely useful in selecting the most appropriate outcome measures among a number of candidate measures for the applied interventions. Further possible applications are the operationalization of concrete ICF categories using specific measures or the creation of ICF category-based item bankings.