ABSTRACT SIMmersion, in collaboration with Binghamton University, Northwestern University, the University of Chicago, and experts from Brown University, propose to develop a standardized, online assessment tool to evaluate Mental Health Clinicians' (MHCs') Cognitive Behavior Therapy skills related to the treatment of anxiety disorders. The proposed project will utilize SIMmersion's PeopleSim technology to develop a series of Virtual Client Sessions (VCS) that are assessed instantly using the Cognitive Therapy Rating Scale (CTRS). The proposed VCS-CTRS provides an innovative approach to identifying and establishing MHC competence in CBT for anxiety disorders, which are currently the most prevalent and highest costing mental health problem in the US. With assistance from leading experts in CBT for anxiety disorders and coding with the CTRS, Aim 1 will focus on developing six virtual sessions with clients varying in age, race, ethnicity, gender, and diagnosis. Using the 11 skill domains outlined in the CTRS, the development team will create 11 scoring algorithms that will allow the VCS-CTRS to automatically generate a CTRS score each time the tool is used. Leveraging the PeopleSim technology will allow MHCs to experience realistic and varied client responses each time the tool is used. Thus, MHCs can use the tool repeatedly, without ever having the same conversation twice. During Aim 2, the research team will recruit 100 MHCs, from novice to expert levels, who will complete two randomly- selected VCS-CTRS simulations and evaluate their experience. The automatic scores generated by the VCS- CTRS will be compared to observer-rated CTRS scores through review of audio recordings and transcripts of the VCS-CTRS sessions to validate the new automated and standardized assessment tool. During Aim 3, the research team will evaluate the feasibility of using the VCS-CTRS, nationally and internationally, to assess MHC's skills and provide feedback regarding areas in need of further development. Master and doctoral level MHCs (N=300) will be recruited to play the two VCS-CTRS sessions that most closely match their self- identified area of clinical expertise. MHCs scores and product evaluations will be analyzed to examine the practical usability and reach of the VCS-CTRS. If successful, additional sessions can be developed to ensure clients seeking counselling receive quality treatment for a range of mental health problems.