Content validation of the Comprehensive ICF Core Set for Head and Neck Cancer (HNC): the perspective of psychologists.

OBJECTIVE The 'Comprehensive ICF Core Set for Head and Neck Cancer (HNC)' is an application of the International Classification of Functioning, Disability and Health (ICF) and represents the typical spectrum of problems in functioning of patients with HNC. The objective of this study was to explore the content validity of this Core Set from the perspective of psychologists. METHODS Psychologists experienced in HNC treatment were asked about the patients' problems, resources and aspects of environment they treat in HNC patients in a three-round Delphi survey. First round responses were linked to the ICF. In round two a list of all identified ICF categories was sent to the participants and they were asked whether the listed ICF categories represent the patients' problems, resources and the aspects of the environment psychologists treat in HNC patients. In round three the participants were requested to reconsider their decisions based on the group response. Kappa statistics was used to describe the agreement between the two health care professionals who performed the linking. RESULTS 34 psychologists from 15 countries named 728 concepts covering all ICF components. 98 ICF categories were linked to these answers. 27 concepts were linked to the not yet developed ICF component 'personal factors'. Kappa coefficient reached 0.71 (95% bootstrapped CI 0.64-0.77). CONCLUSION The validity of the Comprehensive ICF Core Set for HNC was largely supported by the perspective of psychologists. However, some categories considered relevant for psychologists but currently not covered by the Comprehensive ICF Core Set for HNC require further investigation.