This article seems a good (and brief) overview of issues we may encounter transitioning from face-to-face to online teaching. It is not limited to the question of workload, but it does report that online teaching takes up to 40% more time.
Tue, 19 Aug 2014 14:43:00 By: Salman Khan Join the #YouCanLearnAnything movement My 5-year-old son has just started reading. Every night, we lie on his bed and he reads a short book to me. Inevitably, he'll hit a word that he has trouble with: last night the word was "gratefully."