Thinking Scientifically during Participation in a Citizen-Science Project Abstract: A movement has begun recently to involve nonscientists in scientific investigations through projects in which a range of individuals gather data for use by scientists to investigate questions of importance. These projects are frequently referred to as citizen-science projects, and the benefits are assumed to extend beyond the production of important large databases. Those who argue in support of citizen-science projects assume that participants will increase their understanding about the process of science through this engagement in authentic science, in contrast to traditional, tightly scripted school laboratory investigations. However, very little research on the impact of participating in such projects has been carried out. This article examined the letters written by more than 700 participants in a citizen-science project conducted by the Cornell Laboratory of Ornithology. Of these letters, which were unsolicited and not connected with a formal evaluation, nearly 80% revealed that participants had engaged in thinking processes similar to those that are part of scientific investigations. We cannot state that participation in a citizen-science project caused this thinking, but we can say that participation provided a forum in which participants engaged in these habits of thought. The letters also raise some issues about some misunderstandings of science that citizen-science projects should strive to address. This article was written by Deborah Trumbull, Derek Bascom and Anna Cabral of the Department of Education at Cornell University, and by Rick Bonney of the Cornell Lab of Ornithology. It appeared in the journal Science Education in 2000.