Project Summary Evidence across multiple disease areas including HIV care demonstrates that higher quality patient-clinician communication and relationships substantially improves patient health outcomes. It is also well-established that racial and ethnic minorities - African Americans in particular - have consistently lower rates of being engaged in HIV care, be prescribed and adhere to antiretroviral medications, and have higher morbidity and mortality. Evidence suggests that these disparities may rise in part from racial/ethnic differences in relationships and communication between HIV clinicians and patients, which are a potentially remediable source of healthcare inequities. The goal of our project is to develop innovative, valid and scalable measurement and analytic approaches for better understanding of patient-physician interactions that can guide development of interventions to improve the quality of care delivered. This proposal focuses on two innovative features of communication: linguistic style matching (LSM) and linguistic accommodation. LSM is the tendency of participants to use a common vocabulary and speech structure, while linguistic accommodation is the process by which participants in a conversation adjust their language according to the speech style of the other participant. Although there are currently many methods for measuring aspects of patient-clinician communication, no studies to date have explored the role of LSM and linguistic accommodation. Both hold promise as potential mechanisms by which greater social/cultural distance can result in lower quality relationships and outcomes. Accordingly, our specific aims are: (1) Apply computerized text analysis tools to transcripts of clinician-patient interactions to generate novel measures of LSM and linguistic accommodation in HIV care, (2) Evaluate the convergent and predictive validity of LSM and linguistic accommodation to HIV outcomes, and (3) Qualitatively explore examples of visits with high and low LSM and with provider linguistic style dimensions associated with high and low relationship quality. A better understanding of the dynamics of physician and patient interaction in HIV care is necessary to inform continued improvements in HIV care quality and equity. The innovative approach outlined here can: 1) elucidate mechanisms by which HIV clinicians can communicate more effectively and reduce racial/ethnic disparities in HIV outcomes, 2) provide initial validity evidence for a novel communication analytic methods, 3) expand the cost-effectiveness and scale of communication analysis studies of physician-patient interaction, and 4) provide guidance on building real-time feedback systems for HIV clinicians to improve their interactions over time.