I am pleased to be able to introduce a new site – http://equivalencytheorem.info/ created by Terumi Miyazoe from Tokyo Denki University and myself to invite more use, critique and understanding of my 2003 distance education Interaction Equivalency Theorem.

Interaction has always been a defining (but expensive) component of all forms of education. In distance education, we have  expanded the definition of interaction to include that taking place between students and content- in addition to student-student and student-teacher interaction. Randy Garrison and I wrote an article in 1998 detailing the final three forms of educational interaction (teacher-teacher, teacher-content and content-content,- however the 3 student forms are the focus of most DE research and discussion.

In 2003 I began thinking that if you could get one of the three student forms of interaction at very highly levels of both quantity and quality in a formal course, then you have the necessary ingredients for a quality  learning experience – even in the absence of either or both of the other two forms. I expressed these and other ideas in more academic form in the 2003 article, but never took the idea much beyond this because I couldn’t figure out a way to disprove the theory . As the citizendium wiki puts “for a proposition to be considered scientific, it must, at least in principle, be possible to make an observation that would show it to be false. Otherwise, the proposition has, as Karl Popper put it, no connection with the real world.”

Thus, I was most delighted when Bob Bernard and his colleagues published a meta analysis of empirical DE research articles that generally served to support the theorem.  Since then a number of authors and doctoral studies have also confirmed or expanded upon my origional idea. Links to these articles and more is available at the website

Terumi and I welcome suggestions for other links, discussion or expansion of these ideas at the site.


Anderson, T. (2003). Getting the mix right again: An updated and theoretical rationale for interactionThe International Review of Research in Open and Distance Learning (IRRODL), 4(2).

Anderson, T. D., & Garrison, R. D. (1998). Learning in a networked world: New roles and responsibilities. In C. C. Gibson (Ed.), Distance Learners in Higher Education (pp. 97-112). Madison, Wisconsin: Atwood Publishing. – The first manuscript that referred to the fourth interaction dimension of teacher-teacher, teacher-content, and content-content, called Modes of Interaction.

Bernard, M. R., Abrami, P. C., Borokhovski, E., Wade, C. A., Tamim, R. M., Surkes, M. A., & Bethel, E. C. (2009). A meta-analysis of three types of interaction treatments in distance educationThe Review of Educational Research (RER), 79(3), 1243-1289 – A meta-analysis on interaction research in light of the Equivalency Theorem covering 1985 – 2006 empirical studies in distance education.