The Center for Applied Special Technology (CAST) has researched and developed Universal Design for Learning (UDL), an educational framework that recognizes learner variability and aims to provide flexible techniques and materials to meet diverse needs. UDL is based on three principles - providing multiple means of representation, action and expression, and engagement. CAST outlines nine UDL guidelines across these three principles to support the diverse needs and abilities of all learners, including those with disabilities, English learners, gifted students, and others who are marginalized. UDL uses technology and differentiated instruction to customize learning and promote academic progress for all.