CLASSROOM TEST OF SCIENTIFIC REASONING (CTSR) by Anton Lawson, Emeritus Professor of Life Sciences at Arizona State University as of 2013.


You can download the multiple-choice CTSR (password-protected) at either of these locations: in the section on assessments.

Ask for the password to open it.


Alternatively, you can request the multiple-choice CTSR at




You can record scores, analyze them, and correlate them with the FCI, by downloading a zipped spreadsheet called at, under the ‘research’ tab. Prof. James Vesenka developed it.


Graded out of 13, the CTSR maps to Piagetian categories: 0-4, concrete reasoners; 5-7 early transitional; 8-10 late transitional; 11-13, formal.



You can see graphs of national norms at each grade  (7 to 12) for the CTSR at

or in Jacqueline O’Donnell’s Master’s degree thesis, which you can download at in the section on assessments.


Jacqueline O’Donnell’s 33-page thesis, Creation of National Norms for Scientific Thinking Skills …,  is a study of CTSR data on ~5500 students. She found that more than 50% of students in grades seven through nine are concrete thinkers and more than 85% of students graduating from high school are not formal thinkers. You can use these data to track thinking skills development of individual students, classes, and grade levels. The data can help you determine interventions (e.g., CASE) to improve students’ abilities.



You can submit your students’ CTSR data at

or  at



References on classroom use of the multiple-choice CTSR:

*  Interpreting FCI scores: Normalized gain, pre-instruction scores, and scientific reasoning ability, by Vincent P. Coletta and Jeffrey A. Phillips. Am. J. Phys. 73, 12, Dec. 2005.  Others at


*  Using Cognitive Acceleration Materials to Develop Pre-service Teachers’ Reasoning and Pedagogical Expertise, by Nathan Moore, Jacqueline O’Donnell, Dennis Poirier. 2012 ASQ

*  Scientific Literacy: Resurrecting the Phoenix with Thinking Skills, by John C. Deming, Jacqueline R. O’Donnell and Christopher J. Malone.  Science Educator, Winter 2012 Vol. 21, no. 2.

For the above two articles and more resources, email Nathan Moore <>. See also Dr. Moore’s article:


* Lawson, A.E. (2001). Promoting Creative and Critical Thinking Skills in College Biology.

Bioscene 27(1) March. Pages 13-24.  Figure 2 is a graph of pre-test & posttest Classroom Test of Scientific Reasoning (CTSR) scores of 514 college students (non-science majors in Anton Lawson’s course). The multiple-choice version was used, and the maximum score is 13. The gains were HUGE, although no quantities are cited. From Figure 2, we calculated the pretest mean to be ~6.8 and posttest to be ~9.7.  The most frequent CTSR score improved from 7 to 11.  Table 2 is a list of theories (we would call most of them models) and central questions raised in the course.

< Reasoning/Promoting creative and critical thinking in college biology.pdf>


“Basic Theories for Introductory Biology” is a companion to “Promoting Creative and Critical Thinking Skills in College Biology”, by Anton E. Lawson. This unpublished paper elaborates on Table 2 in that 2001 publication.  Dr. Lawson kindly contributed it in 2013. Download both articles at in the section called "Research Results for K-14 teachers".



Free-response versions of the CTSR:

A free-response version makes grading more cumbersome, but you might get deeper

insights into your students' thinking than if you use the multiple-choice version. Two FREE-RESPONSE versions of Anton  (Tony) Lawson's Classroom Test of Scientific Reasoning  (CTSR) are on the ASU Modeling Instruction website, on the webpage called "Weblinks for Modelers":

They are in the section on Assessment.

The password to open them is the same as for the multiple-choice version.


The two versions are:

   a)  12 items, includes combinatorial reasoning. This version is in Tony Lawson's 1995 textbook: SCIENCE TEACHING AND DEVELOPMENT OF THINKING (Appendix F).

   b)  10 items,  includes combinatorial reasoning.  This version was used in Modeling Instruction as early as 1993, and I think that Malcolm Wells used it in the 1980s, for he took Anton "Tony" Lawson's "methods of science teaching" courses at ASU. (Tony Lawson's test has evolved since he developed it in the 1970's.) 

     If you took a mechanics Modeling Workshop prior to 2010, it is in the back of your modeling manual.



How to interpret scores on the CTSR (any version):

   a)  Anton Lawson discusses scientific thinking skills in his 1995 textbook:


       See chapter 2: Patterns of Thinking by Scientists and by Adolescents.

       See pages 444 & 445: scoring the CTSR (the 1995 free-response version).

   b) Download Curriculum Analysis Taxonomies (CAT), by Shayer & Adey, at the ASU Modeling Instruction website, on the "Weblinks for Modelers" webpage, in the section: "Research Results for K-14 teachers" (7 pages, 15 thinking skills, Piagetian).



(This webpage was updated in August 2014 by Jane Jackson.)