Argument Mapping is the best way to improve critical thinking skills

Rationale’s Foundations

Rationale™ is founded on five years of research into thinking skills funded by the Australian Research Council and carried out by the Reason! Project at The University of Melbourne between 2000-2004.

The problem

The central question driving this research was: is there an effective and affordable way to improve critical thinking skills for large numbers of students? The researchers investigated this question in the context of a first-year, one-semester undergraduate subject, Critical Thinking: The Art of Reasoning. Studies at other universities were finding that traditional critical thinking subjects did not appear to add much “value” in terms of improved skills. The challenge was to develop a new method which demonstrably produced substantial skill gains.

The approach

Enrolled students were required to practice reasoning using an argument mapping methodology. This practice was supported by an software package, Reason!Able, developed at the University of Melbourne (and the same team at Austhink Software). The students’ critical thinking skills were measured using the independent and objective California Critical Thinking Skills Test. This was completed at the start of the semester and again at the end. This research was done each year for five years.

Strong gains

The results revealed that students using argument mapping reliably showed strong gains in general critical thinking skills. The results for each student over the semester showed an average 20% improvement during their semester of study. Another way to look at this data is to use the technical notion of effect size. Following one of the leading authorities, Jacob Cohen, researchers generally regard an effect size of greater than 0.5 to be strong or large. The typical effect size in the Reason! Project studies was about 0.8.


Were these gains really due to Reason!Able-based argument mapping? Typically, students in undergraduate courses would be expected to improve with an effect size of about 0.1 over one semester. Those undertaking a traditional critical thinking semester course could expect anywhere between –0.x and 0.42. The research indicates that instruction using the Reason! argument mapping approach improves critical thinking about 8 times more than standard university instruction and approximately double that of the best traditional courses.

Reason!Able and Rationale

While the studies were conducted using Reason!Able argument mapping software, we are confident that similar (or indeed larger) gains would be achieved using Rationale. This is because it is a greatly improved product with argument mapping at its core. Rationale is also developed by the same lead designer and technical director that created Reason!Able.

Further reading

- Twardy, C. R., (2004). Argument Maps Improve Critical Thinking Teaching Philosophy, 27:2

- For more research on how to develop Critical Thinking skills, Critical Thinking & Argument Mapping and Rationale, see here.