The ability to evaluate scientific claims made in various media sources is a critical component of scientific literacy. This study compares how a group of 12th grade students and a group of specialists, including scientists and policy analysts with expertise in global warming, evaluated an editorial about global warming published by an oil company on the World Wide Web. Participants were asked to read the editorial and were asked a set of interview questions about it. Examples from the specialists’ interviews (...) indicate the kinds of responses that are possible with in-depth scientific knowledge. In comparison, although some examples from the students’interviews illustrate competent performance for a nonexpert, other student responses illustrate possible pitfalls. The approach of the present study affords a constructive route for formulating goals for scientific literacy. The approach permits identifying examples of students evaluating scientific claims in more or less competent ways—claims that are in the context of an important socioscientific issue and an actual media source. (shrink)