Philip Guo, an assistant professor of Computer Science at the University of Rochester, summarizes a paper (pdf) he published recently on the optimal video length for student engagement in MOOCs. Amongst his findings were that engagement drops sharply after six minutes, videos produced with a more personal feel could be more engaging than high-fidelity studio recordings, high-quality pre-recorded classroom lectures are not as engaging when chopped up into short segments for a MOOC, and videos that intersperse an instructor’s talking head with PowerPoint slides are more engaging than showing only slides.