This book examines approaches to the evaluation of students' critical thinking on programmatic, school-based, and classroom levels. The first chapter examines the nature of critical thinking and offers a definition as well as an appraisal of the definition. The second chapter looks at methods of gathering quality information on students' critical thinking, focusing on types of information-gathering techniques; comprehensiveness of critical thinking coverage (including aspect-specific, comprehensive, general-knowledge, and subject-specific techniques); and indicators of quality. The third chapter describes commercially available critical thinking tests, including eight comprehensive tests and four aspect-specific tests. Chapter four offers guidelines for making multiple-choice critical thinking tests, with sections on identifying the purpose of the test, making a table of specifications, and drafting items. The fifth chapter suggests open-ended information gathering techniques such as short-answer tests, assigning argumentative essays, interviews, and monitoring classroom discussions. Discussed in the sixth chapter is decision making from information gathered on students' critical thinking, including placement, grading, diagnosis and remediation; program effectiveness; and developmental uses. The final chapter provides a summary and concluding remarks. Suggested readings are provided for most chapters. Also provided are an appendix listing topics for evaluating critical thinking abilities and a glossary. (CR)