A guide on how to develop an International Classification of Functioning, Disability and Health Core Set.

International Classification of Functioning, Disability and Health (ICF) Core Sets are purpose-tailored shortlists of ICF categories from the whole ICF classification for describing functioning and disability. Although the 34 ICF Core Sets developed up to now already cover many health conditions, there may still be a need to develop additional ICF Core Sets that tackle other health conditions and address other purposes. This paper provides a detailed description of the standard process for developing ICF Core Sets that will serve as a guide for future ICF Core Set development projects. ICF Core Sets are developed by means of a three-phase, multi-method scientific process. The process involves four preparatory studies - an empirical multicentre study, a systematic literature review, a qualitative study and an expert survey. The results of the preparatory studies serve as the starting point for a structured decision-making and consensus process at an international conference, during which participating experts decide on the ICF categories to be included in the Comprehensive and Brief ICF Core Sets. The first version of the ICF Core Set may necessitate modifications for specific applications and implementation in specific settings.