Assessing inter-rater agreement of the intellectual disability-frailty index short form: A descriptive pilot study

Frailty is a health concern for many adults with intellectual disability and should be measured to detect at-risk conditions, monitor disease, plan treatment, and gauge mortality. This descriptive pilot study evaluated measurement consistency (inter-rater agreement) of the Intellectual Disability-Frailty Index Short Form among multiple assessors with 20 adults (M age = 48.3 years) who had intellectual and multiple disabilities. Agreement percentages were computed for (a) non-frail, pre-frail, and frail categories derived from total index scores, and (b) each of 17 deficits listed on the form. Low average inter-rater agreement (<85%) was obtained on the index frail categories, several of the assessed deficits had acceptable inter-rater agreement (84.2-100%), while the majority of deficits were associated with moderate-to-low agreement percentages. Though research supports the Intellectual Disability-Frailty Index Short Form as a valid and practical frailty assessment instrument, our findings suggest that full-scale inter-rater agreement must be improved by adding more specificity to the form, clarifying instructions for assessors, and providing competency-based training in assessment implementation.