SUMMARY. This Diversity Supplement would support Robert Ellis, MHA, a talented PhD student in the Health Systems and Population Health program at the University of Washington, who has outstanding potential as an independent NIAAA investigator. Mr. Ellis’ research focuses on how overlapping marginalized identities impact care for AUD. He has designed an innovative dissertation and recruited a strong committee of mentors. Kevin Hallgren, PhD, principal investigator (PI) of the Parent R33 Study (2021-2024) will be Mr. Ellis’s primary mentor; Katharine Bradley, MD, MPH, Site PI of the Parent R33 at Kaiser Permanente Washington, and Chair of Mr. Ellis’ Dissertation Committee, will be co-mentor. The Parent R33 aims to improve measures of unhealthy alcohol use and alcohol use disorders (AUD) documented in electronic health records (EHRs) as part of routine medical care. The R33 uses secondary data from over 700,000 adult primary care patients to evaluate the association of two scaled measures—the AUDIT-C alcohol screen and a validated DSM-5 Alcohol Symptom Checklist—with 5 health outcomes. Specific Aims of the Parent R33 are to evaluate: 1) the associations of AUDIT-C scores with blood pressure, depression, hospitalizations for alcohol-attributable conditions, all-cause hospitalizations, and death, 2) the associations between AUD symptoms and the 5 outcomes after accounting for AUDIT-C scores, and 3) the associations between changes in repeated AUDIT- C measures and changes in risk of the 5 health outcomes. The Parent R33 does not evaluate AUD diagnoses or use of stigmatized labels for AUD; nor does it evaluate outcomes across subgroups based on overlapping identities of sex, race/ethnicity, or socioeconomic status (SES). The proposed Diversity Supplement addresses these issues by evaluating factors associated with medical providers’ documentation of AUD diagnoses in the EHR during routine clinical care. The Specific Aims of the Proposed Diversity Supplement Research are: 1) to describe the probability of adult patients being diagnosed with AUD at primary care visits across subgroups based on the intersections of sex, race/ethnicity, and SES; 2) to describe the probability of being diagnosed with AUD across intersections of sex and race/ethnicity at similar levels of alcohol consumption and AUD symptoms; and 3) to describe the probability of providers selecting a stigmatized label in the EHR when diagnosing AUD based on the intersection of sex and race/ethnicity. Mr. Ellis’ Career Development and Mentoring Plan will support Mr. Ellis as he develops: 1) expertise and skills in alcohol-related health services research and applied disparities research; 2) progressive independence as an investigator, demonstrated by at least 5 publications (3 first-authored); and 3) applies for and obtains a competitive post-doctoral fellowship or an F32 individual fellowship. Mr. Ellis will achieve these objectives via structured and applied training, hands- on mentoring (...