The effects of environment-based education on students' critical thinking skills and disposition toward critical thinking Julie (Athman) Ernst *a and Martha Monroe b a University of MN Duluth, Duluth, USA; b School of Forest Resources and Conservation, University of Florida, USA This study examined the relationship between environment-based education and high school students' critical thinking skills and disposition toward critical thinking. Four hundred four 9 th and 12 th grade students from 11 Florida high schools participated in the study. A Pretest-Posttest Nonequivalent Comparison Group Design (9 th grade) and a Posttest Only Nonequivalent Comparison Group Design (12 th grade) were used. Interviews of students and teachers were used in the classic sense of triangulation. Data collection took place over the 2001±2002 school year. When controlling for pretest score, grade point average (GPA), gender, and ethnicity, environment-based programs had a positive effect on 9 th grade students' critical thinking skills (p=.002). When controlling for GPA, gender, and ethnicity, environment-based programs had a positive effect on 12 th grade students' critical thinking skills (p < .001) and disposition toward critical thinking (p < .001). The results of this study support the use of environment-based education for improving critical thinking and can be used to guide future implementation. Introduction Despite many years of state and national attention, legislation, and discussion, student achievement in core subject areas remains at unacceptable levels throughout the United States (National Commission of Excellence in Education, 1983; National Research Council, 1999). Various efforts are in progress to improve student achievement, including national and state standards and assessments, as well as incentives for improvement and sanctions for continued low performance. At the same time, a number of well-researched reform models and instructional strategies are *Corresponding author: Department of Health, Physical Education, and Recreation, University of MN Duluth, 110 Sports and Health Center, 1216 Ordean Court, Duluth, MN 55812-3032, USA. Email: jernst@d.umn.edu ISSN 1350±4622 (print)/ISSN 1469±5871 (online)/04/040507-16 ã 2004 Taylor & Francis Ltd DOI: 10.1080/1350462042000291038 Environmental Education Research Vol. 10, No. 4, November 2004