Sunday, June 21, 2009

Saba & Shearer's model of transactional distance theory


Roel Cantada

Nephtaly Joel Botor, a classmate of mine at UPOU pointed out to me that my work is similar to a study conducted by Farhad Saba and Rick Shearer in 1994 entitled "Verifying Key Theoretical Concepts in a Dynamic Model of Distance Education"

The abstract of their study states that:

Theory driven, data-based, and empirical studies are needed to verify and solidify distance education's conceptual foundation. The project reported here had two main goals: 1) to empirically verify the concepts of transactional distance, structure, and dialogue, and 2) to develop a methodology for achieving the first goal. Drawing on three different fields--distance education, system dynamics, and discourse analysis--the project measured nine key variables in distance education. Results suggest that transactional distance varies by the rate of dialogue and structure, and demonstrate the value of system dynamics modeling for verifying theoretical concepts in distance education. (Saba & Shearer, 1994)

After reading their work as reported in various sources in depth, I must admit that what I am doing for connectivism is similar to what they did for Moore's Transactional Distance Theory (TDT).

Saba & Shearer's Experiment

Using system dynamics Farhad Saba & Rick Shearer attempted to model Moore's transactional distance and fed the model data through an experiment. The experiment involved an individual learner and individual instructor in two separate rooms. They communicate via what we now call videoconferencing. But it was not integrated, instead they had cameras, tv monitors, separate computers with screen sharing, and telephones. The researchers developed a lesson and video recorded the teaching session.

They only analyzed the audio, and used discourse analysis to categorize the discussion. Then they used the frequency of each category as data in the model. So time is also a variable in their experiment. They used STELLA to simulate the interaction in the model.

I got lost with the language of systems dynamics because it is different from graph theory. What I gathered is that the model only used two nodes to represent structure and dialogue. The other TDT elements where kept constant or merged with these two.

They found that there was an inverse relationship between dialogue and structure (as they defined these variables). (Saba & Shearer, 1994)

Difference between Saba & Shearer and my current work

First as I have mentioned is that they modeled TDT, while I am trying to model connectivist distance learning.

Second is that there is a difference in how we modeled transactional distance theory itself. Note that I claim to be able to subsume earlier distance learning theories in my model which is why I showed hypothetically how TDT can be modeled within connectivism.

I think Saba & Shearer only modeled the dynamic attributes of structure and dialogue. And they made all the other elements of TDT constant. Jon Dron (2007, p.22) said that "Saba's merging of learner autonomy and dialogue is slightly at odds with Moore's interpretation...". Furthermore Dron (2007, p.22) said "Moore sees autonomous learning as something quite distinct from that which occurs as a result of dialogue or structure. For Moore, autonomous learners are those who can cherry-pick the sources of learning they need, freed from the impositions of structure or the need for dialogue."

I have modeled learner control (not necessarily learner autonomy) as distinct from dialogue. I consider learner control as vertical a relation between the learner x learning environment x concept. While dialogue is a horizontal relation between actor (including learner) x actor or mediated by the learning environment (e.g. cmc) such that actor-learning_environment-actor. See

Third is that they gathered data from videoconferencing, while my intention is to gather primarily from online learning and then all delivery modes of distance education.

Finally, after 15 years I believe that much has changed not only in technology but also in the tools for network analysis that we can leverage in this approach.

But I am very happy that my classmate pointed this out to me. It's encouraging to find out that my ideas are not that crazy after all. I must give credit to Saba and Shearer for their pioneering work. I hope to learn from their methodology in my own study.


Dron, J. (2007). Control and constraint in e-learning: Choosing when to choose. USA & UK: Idea Group.

Saba, F., & Shearer, R. L. (1994). Verifying key theoretical concepts in a dynamic model of distance education. In American Journal of Distance Education, 8(1). Retrieved June 21, 2009, from

Saba, F. (2003). Distance education theory, methodology, and epistemology: A pragmatic paradigm. In Moore, M.G., & Anderson, W.G. (eds.). Handbook of distance education. New Jersey: Lawrence Erlbaum.

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