Prior research on pair programming has found that compared to students who work alone, students who pair have shown increased confidence in their work, greater success in CS1, and greater retention in computer-related majors. In these earlier studies, pairing and solo students were not given the same programming assignments. This paper reports on a study in which this factor was controlled by giving the same programming assignments to pairing and solo students. We found that pairing students were more likely to turn in working programs, and these programs correctly implemented more required features. Our findings were mixed when we looked at some standard complexity measures of programs. An unexpected but significant finding was that pairing students were more likely to submit solutions to their programming assignments. Categories and Subject Descriptors K.3.2 [Computer and Information Science Education]: Computer Science Education General Terms experimentation, measurement Keywor...