Toward an Ungraded CS50 - SIGCSE 2021

In 2010, we proposed to eliminate letter grades in CS50 at Harvard University in favor of Satisfactory/Unsatisfactory (SAT/UNS), whereby students would instead receive at term's end a grade of SAT in lieu of A through C- or UNS in lieu of D+ through E. Albeit designed to empower students without prior background to explore an area beyond their comfort zone without fear of failure, that proposal initially failed. Not only were some concentrations on campus unwilling to grant credit for SAT, the university's program in general education (of which CS50 was part) required that all courses be taken for letter grades. In 2013, we instead proposed, this time successfully, to allow students to take CS50 either for a letter grade or SAT/UNS. And in 2017, we made SAT/UNS the course's default, though students could still opt out. The percentage of students taking the course SAT/UNS jumped that year to 31%, up from 9% in the year prior, with as many as 86 of the course's 671 students (13%) reporting that they enrolled because of SAT/UNS. The percentage of women in the course also increased to 44%, a 29-year high. And 19% of students who took the course SAT/UNS subsequently reported that their concentration would be or might be CS. Despite concerns to the contrary, students taking the course SAT/UNS reported spending not less but more time on the course each week than letter-graded classmates. And, once we accounted for prior background, they performed nearly the same. We present the challenges and results of this 10-year initiative. We argue ultimately in favor of SAT/UNS, provided students must still meet all expectations, including all work submitted, in order to be eligible for SAT. *** This is CS50, Harvard University's introduction to the intellectual enterprises of computer science and the art of programming. *** HOW TO SUBSCRIBE http://www.youtube.com/subscription_center?add_user=cs50tv HOW TO TAKE CS50 edX: https://cs50.edx.org/ Harvard Extension School: https://