Deeper examination of what "best practices" evidence shows connect teaching methods to the development of the Partnership for 21st Century Learning's 4C framework[13] and the competencies identified in the Hewlett model for deeper learning,[14] give a sharper picture of "what works" in terms of instructional strategies and tools. For instance, the Marzano Lab has identified the high effects of cooperative learning to develop collaboration, graphic organizers to advance critical thinking, feedback to sharpen communication, advance organizers to enrich entry activities in PBLs, etc.[15] John Hattie's meta-analysis of visible learning is even more specific.