Students read six documents that varied in terms of their perspectives on a scientific issue and the trustworthiness of the source features. After reading, students wrote essays, rank-ordered the documents according to perceived trustworthiness, and provided reasons for their rank-order decisions. Students put the most trust in a textbook and a public information text, primarily giving content reasons for their trustworthiness judgments. The kind of source characteristics that students drew upon when deciding what to trust and what not to trust varied across documents. Finally, their source evaluation was related to the source citations included in their essays.