John: Lé onie and Gina's article represents an important initial effort to address the role that museums in general and natural history museums in particular play in supporting the public's understanding of science. Certainly it seems totally reasonable to use traditional views on science literacy-practical, civic, and cultural (and economic) as a framework for assessing museum's impact. That said, I wonder if taking this orthodox approach to defining scientific literacy is really all that helpful. Given the brief and typically a-contextual nature of most natural history museum visit experiences, what expectations should we have that these unique experiences would dramatically and measurably influence public understanding and beliefs? The implication in this article is that they should, but is this really a fair question to ask?Lé onie and Gina: We are pleased John has drawn attention to a question of central importance: Is it reasonable to expect the impact of a brief visit to a cultural institution such as a natural history museum to produce an immediately measurable impact on the public's understanding and beliefs about science? This question is particularly salient for three reasons. First, because most visitors do not attend for the explicit purpose of learning about science (for example, only 28% of our visitors gave their purpose as education), is it reasonable for us, in a sense, to ''go fishing'' for findings that indicate such an impact? Second, as John points out, is our orthodox approach to scientific literacy a reasonable way to quantify change in understanding and beliefs? Third, how reasonable is it to expect an almost ''instant impact'' from the museum visit, which is what a pretest-posttest design like ours is limited to measuring?We can only partly answer these questions. Our approach to scientific literacy drew from several sources. First, we were impressed with the sensible approach suggested by St. John and Perry (1993) to investigate impact in terms of how visitors