The Lawton and Brody a half century later: A case for contemporary revision.

Objective: To reevaluate the psychometric properties and contemporary relevance of the 1969 Lawton and Brody Instrumental Activities of Daily Living (iADL) Scale in older adults. Methods: Data from 3552 participants and co-participants in the Texas Alzheimer's Research and Care Consortium cohort were analyzed. Lawton and Brody iADL Scale items were analyzed in a sample with no cognitive disorder, mild cognitive impairment, and dementia. Graded response models assessed item discrimination and difficulty, with differential item functioning (DIF) analyses examining demographic effects. Expert reviewers evaluated item content for cultural and technological relevance. Results: Items assessing shopping, food preparation, and transportation were most sensitive to mild functional impairment, while the total scale had limited detection of subtle functional decline. Statistical DIF emerged on 75% of items, whereas clinically meaningful DIF for several demographic groupings emerged on the transportation item. Expert reviewers identified outdated content, particularly for telephone and financial items, reflecting technological shifts. Broader changes in normative behaviors and sample demographics may further challenge scale applicability. Conclusions: The Lawton and Brody iADL Scale remains foundational but shows limited sensitivity for early functional decline. Outdated items and evolving socioeconomic and technological contexts underscore the need for refinement to enhance unbiased early detection and maintain longitudinal comparability. Updating the instrument to reflect modern demands could strengthen functional assessment in Alzheimer's disease and related disorders research and clinical trials.