Each school year, millions of children participate in organized field trips to museums, zoos, aquaria, and nature centers. Naturally, school groups represent a significant percentage, if not an outright majority, of visitors to such informal educational institutions. Educators at these institutions must often direct the greatest proportion of their time and effort towards educational programming for the streams of visiting school groups. Understandably, many informal educators have a strong interest in evaluating the impact of their efforts directed towards young visitors. Museum education