Your first query: Start with children's museums and science centers
where most often staff is found in exhibitions...as "explainers" or
as monitors or as observers of their visiting publics. A place like
the Exploratorium in San Francisco may have done some studies on
explainers. Or try the Indianapolis Children's Museum or the
Boston Children's Museum...perhaps some evaluations have been done in
those places. They have been pretty successful wherever they are used.