Project Summary/Abstract The proposed Measurement Core of this Developmental AIDS Research Center will support researchers to develop, adapt, and incorporate improved measurement of stigma into their HIV and mental health research to meet the Center's overarching goal to improve response to stigma as a threat to mental health and individual- and population-level HIV outcomes. Specifically, the Stigma Measurement Core's goal is to support the creation and use of rigorous stigma assessment strategies that incorporate quantitative, qualitative, and mixed methods to better characterize relationships between stigma, mental health - including depression, anxiety, and drug/alcohol dependency - and HIV outcomes in epidemiologic investigations, intervention research, and program implementation science. Despite a proliferation of research on stigma within the HIV epidemic, a significant dearth of rigorous stigma research still exists in key areas of the HIV treatment cascade and in the roll out of new prevention methods. Additionally, important gaps in our understanding of how to best assess and characterize stigma persist; for instance, how to harmonize across a multitude of commonly used scales with populations for whom measures do exist, to create standardized scales when possible without compromising validity and utility in diverse settings, adapting and validating metrics for other understudied populations, simultaneous consideration of empowerment factors and a strengths-based approach, and ways to understand structural stigma including efforts to characterize intersectional stigma from a systems. Further, while there is a significant body of research on mental health among people living with HIV, rigorous study of how mental health and substance use may play a role on the pathway between minority stressors including stigma and HIV outcomes and exacerbate experiences of stigma continues to be needed. Building upon existing collaborative research between JHU and Emory to better understand stigma and mental health as drivers of the HIV epidemic, we propose the following Measurement Core specific aims: Aim 1. To expand the rigorous development, adaptation, and validation of measures of stigma processes occurring at multiple socioecological levels related to diverse identities, behaviors, and conditions relevant to HIV research. We will accomplish this aim by fostering interdisciplinary collaboration among HIV, mental health, and social science researchers across our institutions. Aim 2. To promote the use of validated stigma scales in epidemiologic and intervention mental health and HIV research. We will curate and make available an online, searchable library of publicly available tools to assess stigma and mental health among populations affected by or at high risk of HIV. Aim 3. To support the development of analytic skills for characterizing the complexities of the interrelationships between stigma, mental health and HIV related outcomes. 1