Fundamental Training for Formal and Informal STEM Mentors - The United States is experiencing a shortage of young people pursuing and remaining in STEM majors and careers. Identifying effective strategies to attract and retain youth in STEM education and careers is crucial. One promising strategy to excite, recruit, and retain youth in STEM is youth participation in a STEM mentoring program. These programs include the provision of both formal, assigned mentors, as well as the provision of informal mentoring relationships that develop naturally during participation in STEM programming. Regardless of the type of mentoring relationship or the specific STEM activities conducted during the program, the daily interactions and relationship between mentors and youth can have a profound impact on the youth. Mentor training has been shown to support the development of close, enduring mentoring relationships; however, no mentor training product specific to youth STEM mentoring exists. Comprehensive training is needed for formal and informal mentors so they understand the unique needs of youth who have limited access to STEM professionals and experiences, build supportive relationships, encourage STEM engagement and persistence, and promote STEM identity and self-efficacy. The main purpose of this project is to complete the development of and evaluate the impact of the EmpowerSTEM mentor training program and support resources on STEM-related outcomes. The content of EmpowerSTEM is tailored to the unique needs of youth in STEM, based upon research associated with the recruitment and retention of youth into STEM education and careers, and builds upon previous successes in providing core, pre-match, web-based mentor training. In addition to tailoring training to the needs of formal and informal mentors in skills related to STEM success, staff of youth-serving STEM programs need the ability to customize online training content to meet the unique needs of their program, sometimes adding or deleting lessons, depending upon the program’s model or requirements. Thus, a second goal of this project is to enhance the flexibility of iRT’s eTrove software, a learning (LMS) and project management software platform. In Phase II, we will: 1) Obtain detailed feedback from STEM mentoring program staff, mentors, and consultants to inform the content and design of the final product, 2) Complete development of the web-based, mobile-friendly EmpowerSTEM training and support resources, 3) Enhance the eTrove software to allow STEM program staff to customize, deploy, and monitor engagement and completion of their training requirements, and 4) Conduct a randomized controlled trial of the EmpowerSTEM training on proximal mentor outcomes that are associated with more effective STEM mentoring relationships. The EmpowerSTEM training and eTrove software will have a significant impact on the effectiveness of STEM mentoring relationships by promoting the interest, engagement, and persistence of youth in STEM education and careers, fostering a more prepared and larger STEM workforce.