Mode of administration effects on disability measures in a sample of frail beneficiaries

Purpose: To compare disability rates resulting from several modes of survey administration in a single sample of frail elders. Design and Methods: Using the same battery of six ADL questions we compared the resulting level of disability across several modes of administration: mail survey with telephone follow-up, in person interview, and evaluation by a registered nurse, further comparing self and proxy responses where both were available. We also created a crosswalk between these measures and clinical evaluations by rehabilitation therapists, allowing another point of comparison. Results: Disability rates varied substantially by mode of survey administration and all survey modes yielded lower rates of disability than those we derived from clinical assessments. Implications: Relying on self-report in evaluating functional status may underestimate disability in clinical evaluations, level of care determinations and service planning. Researchers and policymakers should also take mode of administration effects into account when estimating or comparing disability rates.