In reply to Reach>Talent:
How about a LAV? (Light Annoyance Value). As in how annoying do you find the rear lights of certain VW (and other makes) cars that have LED lamps that flicker?
Old fashioned lamps have a certain amount of thermal/phosphorescence inertia, but some LED lamps can be really distracting/annoying.
Some people don’t see the flicker/shimmer at all, but others do (a non scientific survey done by me, seems to indicate that those who play computer games are the most sensitive to this phenomena).
OK, I have to admit a professional interest in this subject as I have been testing dimmable LED lamps recently and there is no official specification of the subject.