An interesting report on the Casting Out Nines Blog (part of the Chronicle of Higher Education Blog Network): Who does screencasting help the most? The author summarizes the results of a Winter 2011 paper in Advances in Engineering Education (PDF), and concludes that,
I think it suggests that screencasts, when done well and deployed properly, help all students – they certainly don’t hurt – and they help most thise (sic) students who need the most help. The analogies to mathematics courses are clear. In any math course there will be a large contingent of students whose backgrounds aren’t congruous with the course: students whose prior math background is weak to rusty, students from non-STEM disciplines, and so on. For those students, if they use the screencasts, then they may be likely to improve at a surprisingly fast rate.
Not earth-shattering, but encouraging. Keep on screencasting!