ICF Linking and Cognitive Interviewing Are Complementary Methods for Optimizing Content Validity of Outcome Measures:...

Area of Science:

• Health Services Research
• Rehabilitation Medicine
• Measurement Science

Background:

• Content validity is crucial for outcome measures, ensuring they accurately assess constructs.
• The International Classification of Functioning, Disability and Health (ICF) provides frameworks for evaluating outcome measure content.
• ICF Core Sets serve as international standards for key constructs in various health conditions.

Purpose of the Study:

• To define content validity and explore the application of ICF linking rules and Core Sets in outcome measure validation.
• To propose methods for assessing respondent engagement with outcome measure content.
• To analyze current practices in ICF-based content validation and identify best practices.

Main Methods:

• Review of operational needs and existing definitions of content validity.
• Application of ICF linkage rules (2002, 2005, 2019) and ICF Core Sets as reference standards.
• Proposal of summary indicators for ICF linkage (e.g., Measure to ICF linkage, Core Set Representation).
• Development of a framework for classifying respondent engagement using cognitive interviewing (e.g., Clarity/Comprehension, Relevance).
• Analysis of 24 manuscripts using ICF linking for content validation.

Main Results:

• Authors commonly use ICF linking to validate existing measures, often employing 2005 rules and summarizing content at a conceptual level.
• ICF linking is infrequently used for creating new measures or applying the full scope of 2019 rules.
• Integration of ICF linking with qualitative methods like cognitive interviews is rarely reported.
• Proposed summary indicators and respondent engagement frameworks are underutilized.

Conclusions:

• ICF linkage is a powerful tool for ensuring the content validity of patient-reported outcome measures (PROMs) during development and validation.
• Best practices include using updated ICF linking rules, triangulating ICF linking with cognitive interviews, and applying defined summary indicators.
• Further research should focus on integrating ICF linking with qualitative methods and utilizing advanced summary indicators for robust content validation.