effects of a single visit from other factors that could be contributing to positive learning outcomes. And arranging for tests before and after the experience or setting up other traditional measures in many museums and science centers can be disruptive, or even inappropriate for the purpose that assessment may serve (for instance, assessment that is part of exhibit or program design and improvement). Thus, it is important to consider the rationale for assessing learning in informal science learning settings.
Another feature of informal science learning environments that creates challenges for assessment is that experiences cannot fully be prescribed or predetermined. Rather, the environments are learner-centered; so much of what happens emerges during the course of activities. Because each visitor, participant, or audience member seeks out his or her own unique experience, it is extremely difficult to establish a uniform intervention or activity that succeeds in assessing the overall impact of the informal science environment. Part of the problem, too, is the importance of not interfering with the unique, free choice or self-directed experience itself, because it is often that particular characteristic that inspires learning in the first place. The challenge thus becomes how to document the learning that occurs while not sacrificing the freedom and spontaneity that is integral to the experience.
The collaborative and social aspects inherent in many informal experiences also pose a challenge for assessing learning. Participants in summer camps, science centers, family activities, hobby groups, and such are generally encouraged to take full advantage of the social resources available in the setting to achieve their learning goals. The team designing a submersible in camp or a playgroup engineering a backyard fort can be thought of as having implicit permission to draw on the skills, knowledge, and strengths of those present as well as any additional resources available to get their goals accomplished. “Doing well” in informal settings often means acting in concert with others and accomplishing results in the process. Thus, assessments that focus on an individual’s performance alone may “under-measure” learning because they fail to take into account the material and human resources in the environment, even though making use of such resources is a hallmark of competent, adaptive behavior.1 In addition, assessing whether participants working in a group have grasped the science is important, but measuring the role that collaboration and problem solving have played in learning may be equally so. Teasing out this variable from individual assessment has proven to be difficult, and some have challenged the rationale for doing so in the first place. In addition, the learning accomplishment might be integral part of the experience—the back-