Garr Reynolds on that hairy chestnut called Powerpoint.
"It is effective to speak to a diagram, because it presents information in a different form. But it is not effective to speak the same words that are written, because it is putting too much load on the mind and decreases your ability to understand what is being presented." — John Sweller
Garr sums up what I think and have been banging on about for some time: If your “PowerPoint deck” can be perfectly and completely understood without your narration, then it begs the question: why are you there?