What happens when there is institutional support for faculty to collect and analyze learning assessment data with a focus on equity? Drawing on the results of equity-focused assessment studies in STEM programs, this presentation highlights the key findings, challenges, and implications for teaching and assessment practices such as designing student-centered assessment and sharing insights of assessment results with students. Challenges include planning and conducting assessment in a sequence of courses - a collaborative process that starts with mapping of knowledge and skills students need to develop in lower-division courses to succeed in upper-division courses. We will discuss specific examples and suggest forms of institutional support for effective, collaborative, faculty-led efforts to identify and address achievement gaps in STEM and other programs.