K-12 educators who engage their students in designing using digital technologies face the challenge of teaching the act of designing in classroom contexts, yet books and articles on the topic of design processes and methods tend to focus on the instruction of design strategies for adult learners rather than children. One framework, the Informed Design Teaching and Learning Matrix (Crismond and Adams, Journal of Engineering Education 101:738-797, 2012) does address dimensions of design practices and instructional approaches specifically within K-16 educational contexts, but it has yet to be revised based on empirical evidence. Using multiple case studies, we examined this framework against teacher perceptions of how design should be taught and the observed instructional practices of those secondary educators. We argue that refinement to the IDTL Matrix is warranted and suggest expanding the framework to include design strategies that address collaborative learning, peer communication, and the integration of digital and non-digital tools and materials. Such revisions to the IDTL Matrix would contribute to providing the best possible support to teachers who seek to develop their students' design strategies in classroom contexts.