The relationship between students' use of PeerWise, an online tool that facilitates peer learning through student-generated content in the form of multiple-choice questions (MCQs), and achievement, as measured by their performance in the end-of-module examinations, was investigated in 5 large early-years science modules (in physics, chemistry and biology) across 3 research-intensive UK universities. A complex pattern was observed in terms of which type of activity (writing, answering or commenting on questions) was most beneficial for students; however, there was some evidence that students of lower intermediate ability may have gained particular benefit. In all modules, a modest but statistically significant positive correlation was found between students' PeerWise activity and their examination performance, after taking prior ability into account. This suggests that engaging with the production and discussion of student-generated content in the form of MCQs can support student learning in a way that is not critically dependent on course, institution, instructor or student.