PROJECT SUMMARY Of the 26 million new sexually transmitted infections (STI) in 2018, almost half were among adolescents (15-19 years old) and young adults (20-24 years old). Millions of cases remain undiagnosed and untreated, particularly among male teens. Less than 3% of sexually active male teens have had an STI test in the past 12 months versus 26% of their female peers. Male teens are more likely to forego testing than female teens due to greater confidentiality concerns, cost/insurance barriers, and lower self-perceived risk. COVID-19 has exacerbated barriers to STI care, as testing services have plummeted by 66% since March 2020. There is great urgency to develop innovative and effective methods to screen adolescent males for STIs: as males are largely asymptomatic, their untreated STIs can be transmitted unknowingly to other sexual partners. Untreated STIs can lead to male and female infertility and increase one’s susceptibility to contracting HIV. The objective of this R21 is to use an innovative, user-centered approach, a discrete choice experiment, to determine the preferences for STI testing models among Black adolescent males. In a discrete choice experiment (DCE), a methodology that has been widely used to inform the design/adoption of health services, respondents are presented with two services with different attributes and are asked to choose which one they prefer (e.g., Testing Model A or B). This series of choice-tasks elucidates the relative importance of certain attributes as well as acceptable trade- offs. Importantly, DCEs can be used to highlight shared but distinct preferences within different groups of Black adolescent males, which may justify the development of multiple, tailored STI testing models. The Early- Investigator-led team, with extensive expertise in recruiting Black youth, will accomplish this objective through two aims: Aim 1 will build the DCE collaboratively with a community-based Youth Advisory Board comprised of 15 Black male adolescents from Atlanta, GA. Qualitative methods such as interviews, focus groups, and pile- sort exercises will be used to define the testing attributes (e.g., test location, time till results) which are most important to youth; these attributes will be integrated into the experimental design of the DCE. Aim 2 will leverage multi-platform community-based and online strategies to recruit a heterogenous sample of 500 Black male adolescents to participate in a 15-minute online DCE. A latent class analysis will be used to elucidate preference heterogeneity for STI testing, explore groups or classes with distinct attribute preferences, and assess associated behaviors/characteristics. The research approach will be anchored in DCE best practices and in the Phenomenological Variant of Ecological Systems Theory, a framework that recognizes the unique contexts in which Black youth develop. This R21 innovatively explores a growing health disparity in a population often neglected in research. A...