The Harvard Graduate School of Education’s Project Zero defines Visible Thinking as “a flexible and systematic research-based conceptual framework, which aims to integrate the development of students' thinking with content learning across subject matters.” The Project has distilled this framework into several thinking routines that are simple protocols for exploring ideas and make students thinking visible. Teachers are encouraged to integrate these routines into daily classroom life and use them with their students to extend and deepen their thinking. These easy-to-learn mini-strategies are focused on four "thinking ideals" – understanding, truth, fairness, and creativity.