providing adults with opportunities to gain scientific knowledge (Strand 2), test and explore the physical world (Strand 3), understand science as a way of knowing (Strand 4), and develop positive attitudes toward science (Strand 6). They are often organized and administered through scientific organizations, such as university-based labs and local environmental groups. The broad goals of citizen science include enabling scientists to conduct research in more feasible ways than they could without the participation of volunteers and promoting the public understanding of science. As Krasny and Bonney (2004) have noted, citizen science may also engage nonscientists in decision making about policy issues that have technical or scientific components and engage scientists in the democratic and policy processes. The specific focus of a given volunteer science program may include basic scientific goals, such as tracking migratory species, gathering climate data, or documenting species behavior (Cornell Lab of Ornithology, 2008). Or programs may focus on changing behavior (e.g., preservation/environmental goals) or be closely linked to informing particular policy concerns.
A project funded by the National Science Foundation (NSF) designed to enhance the ability of citizen science projects to achieve success had identified, by November 2007, more than 50 published scientific articles based on citizen science data, along with other articles assessing the data quality, educational processes, and impact of citizen science projects (http://www.citizenscience.org). For example, the Community Collaborative Rain, Hail and Snow Network is primarily concerned with a basic science issue—gathering data on weather patterns in the central Great Plains region of the United States (Albright, 2006). Trained volunteers, including adults and children, used inexpensive instruments to measure precipitation across the region, which typically was highly variable. Data collected through the network provided scientists with detailed local precipitation data and supported more sophisticated weather modeling.
Other programs focus on basic scientific questions that have clear policy implications. For example, Lee, Duke, and Quinn (2006) reported on Road Watch in the Pass, which engaged citizens in reporting wildlife sightings along a stretch of highway. The dataset generated new insights into the location of automobile-wildlife collisions that were not evident in models previously developed, providing important, empirically established guidelines for policy makers as they planned road maintenance and construction.
The number and scale of citizen science programs is increasing (Cohen, 1997; http://pathfinderscience.net/; http://www.citizenscience.org). The effects of these projects on participants’ knowledge and attitudes toward science have rarely been documented (Brossard, Lewenstein, and Bonney, 2005), although efforts to increase assessment are actively in progress (http://www.citizenscience.org). The current evidence base sheds some light on participant learning; however, it is limited and in some ways contradictory, as illustrated in the literature reviewed below. To show the promising nature