Abstract
This paper presents the results of a CS0 course based on the Scratch programming language that was designed to improve the retention of at-risk computer science majors. At the authors' university, prior to the introduction of the CS0 course, students who selected the computer science major but entered the university with weak mathematics preparation from high school left the major at a high rate. The Scratch-based CS0 course was developed to keep the students who had a desire to major in computer science engaged in the department, as well as prepare them for success in future computer science courses. This paper discusses the formal study that was conducted on the CS0 course offerings in Fall 2009 and Fall 2010, which reached about 120 students total, and over 60 in the target group of freshman CS majors with low mathematics placement scores. The study examined the course's effectiveness at improving the retention, performance and attitudes of these at-risk majors.