The course materials students are expected to utilise in online instruction vary. Studies have shown that students tend to enjoy online courses with lecture videos more than those without, but few studies have measured the impact of lecture videos on student outcomes. Do lecture videos increase student understanding and retention, thus improving student outcomes? Students were provided with one or more study aids, video lecture, PowerPoint or instructor-created notes for learning about the role of the Electoral College in US presidential elections. We assessed student retention and understanding of the Electoral College with a quiz as an indicator of student outcomes. We found that the video lecture in combination with a PowerPoint was the most effective study aid.