ABSTRACT This supplement application identifies and organizes health questions and measures of Alzheimer's Disease and Alzheimer's Disease Related Dementias (AD/ADRD) and other cognitive impairments using longitudinal studies supported by the National Institute on Aging (NIA). Specifically, the supplement targets high impact studies identified as “Tier 1” studies in the NIA 2016 Data Infrastructure Review. The National Archive of Computerized Data on Aging (NACDA) mission is to create a dynamic and flexible data infrastructure to stimulate health research and advance knowledge related to the gerontological lifecourse. This supplement application builds upon our work “Creating an Interoperability Data Infrastructure for Research on the Aging Lifecourse” funded by NIA (R21AG073358-01). This research grant seeks to accomplish three critical goals central to the work of the proposed supplement 1) Identify- core elements of aging data need to be formally cataloged and structured at the metadata level. This process includes variable-level information and concepts using a "Common Data Elements" (CDE) approach; 2) Integrate- relate independent longitudinal studies to each other across health thematics, establishing an XMI/DDI template to allow cross-study analysis using DDI Lifecycle markup; Operationalize- make the data resources available to the research community, provide ongoing support, and training for the interoperability portal. The project will provide training and educational services through conference presentations, workshops, and online webinars. The proposed supplement will address these goals by identifying variables measuring AD/ADRD and other cognitive impairments within Tier 1 studies as well as sociodemographic, and comorbidity data commonly associated with increased risk of AD/ADRD.