Does adapting a self-report instrument to improve its cognitive accessibility for people with intellectual disability result in a better measure? - A cognitive interview study

Background and aims: We investigated whether improving the cognitive accessibility of a widely used self-report measure leads to better understanding and more accurate answers in a sample of adults with mild intellectual disability and borderline intellectual functioning.

Methods and procedures: We undertook a series of cognitive interviews before and after adaptation of the instructions and selected items of an existing self-report measure of adaptive functioning. Interview results and participant feedback were supplemented with quantitative comparisons between participant and carer scores.

Outcomes and results: Adaptation based on participant experiences and preferences combined with evidence-informed guidelines improved understanding and accuracy. Self-report and carer-report scores showed greater convergence after adaptation; this occurred because people with intellectual disabilities appeared to understand the self-report measure more effectively.

Conclusions and implications: The results show that adaptation of the self-report instrument to suit the needs and preferences of people with mild intellectual disability or borderline intellectual functioning leads to a more accessible measure and more reliable and valid results. Results also highlight the importance of complementing proxy reports with a first-person perspective in assessment as clients and informants may differ in their assessment of behavior and skills.