Computer Science Teacher Preparation to Address Bloom's 2 Sigma Problem in the Post-COVID19 Age

The COVID-19 pandemic has triggered us to explore a new teacher preparation paradigm aligned with Bloom's one-to-one and mastery learning vision. In 1984, Benjamin Bloom reported a phenomenon he named "The 2 sigma problem". In a series of studies, Bloom found that combining one-to-one tutoring and mastery learning techniques increased the average student performance by two standard deviations compared to traditional instructional methods. Bloom referred to this phenomenon as a problem given the infeasibility of implementing such instructional strategy on a large scale and invited educators to search for feasible alternative solutions. While pedagogical and technological innovations, such as Intelligent Tutoring Systems and Massive Open Online Courses have emerged, traditional instructional methods (e.g., a teacher lecturing) and structures (e.g., class size), still dominate the public educational system. The proposed paradigm combines the development of teaching for mastery and teaching one-on-one competencies. For addressing mastery learning, the pre-service teachers created asynchronous short videos followed by tasks for high school CS pupils. For addressing one-to-one tutoring, each student was paired with a high school pupil and tutored him\her for one hour per week for eight weeks synchronously via Zoom. The proposed teacher preparation model suggests a scalable and sustainable learning environment that enables a smooth transition from face-to-face to online learning while addressing the 2 sigma problem.