In the book, The Rationality Quotient, authors Keith Stanovich, Richard West, and Maggie Toplak, show that rational thinking, like intelligence, is a measurable cognitive competence.  Drawing on theoretical work and empirical research from the last two decades, they present the first prototype for an assessment of rational thinking analogous to the IQ test: The CART (Comprehensive Assessment of Rational Thinking)

The authors describe the theoretical underpinnings of the CART, distinguishing the algorithmic mind from the reflective mind.  They discuss the logic of the tasks used to measure cognitive biases, and they develop a unique typology of thinking errors.  The Rationality Quotient explains the components of rational though assessed by the CART, including probabilistic and scientific reasoning; the avoidance of “miserly” information processing; and the knowledge structures needed for rational thinking.  Finally, the authors discuss studies of the CART and the social and practical implications of such a test.  Sample items from the test are available in the appendix.