Dr. Barry Willis published a survey of distance learning research in 1994. He concluded that most important predictor of learning outcomes was the amount of interaction and feedback.

"Results from a multitude of studies suggest that the media itself is not as important to instruction as other variables, such as learner characteristics, motivation and instructional alternatives. There is little empirical evidence to support the current drive for live and interactive instruction... What does seem to be very important is support for the distance learner. Students want and need rapid feedback..." - p. 62

"The research literature doesn't confirm the need for live or synchronous interactivity in distance education. Its impact on learner outcome is elusive at best." - p. 49

-- Distance Education Strategies and Tools, Barry Willis (Editor), Educational Technology Publishers, Englewood Cliffs, NJ, 1994

In a study of students taking videotaped courses, researchers concluded:

"no matter how well produced videotaped lessons may be, lack of a teacher (to interact with) greatly reduces the effectiveness of the teaching approach."

-- Interactive Satellite Instruction: How Rural Schools Benefit, B. Barker, Paper presented at the Annual Conference of the Rural Education Association, Little Rock AR, 1986

Markwood and Johnstone's study of distance education indicated that asynchronous interaction from computer conferencing and voice mail was key to effective instruction.

-- New Pathways to a Degree, Markwood & Johnstone, Western Cooperative for Educational Communications, Boulder, CO, 1992