John Dewey (1933) argued that reflective thinking, the careful collection
and evaluation of evidence leading to a conclusion, should
be a central aim of education. Recent national reports on the quality
of post-secondary education in the United States have affirmed the
centrality of teaching critical thinking skills to college students
(National Institute of Education 1984; Association of American
Colleges 1985; Garrison 1984). Yet the empirical evidence documenting
progress toward this objective among undergraduate college
students is minimal, and among graduate students, is virtu-