E-learning Instructional Design Guidelines - Human Factors ...

HFIDTC/WP2.1.5/2
Version 2/ 30 April 2006
3.2.2 Interaction with students
Figure 2 - Interaction with facilitator
The degree of individual interaction within a group is negatively related to group size (i.e.
the larger the group the lower the degree of individual interaction). As the group expands
the number of potential interactions within the group becomes very large – with 3
individuals there are 3 potential interactions, with 12 individuals there are 66 potential
interactions (the scaling of the number of interactions follows Metcalfe’s Law/2). This is
illustrated in Figure 3. Potential interactions = (N x (N-1)) / 2.
Figure 3 - Interaction with students
In the synchronous situation, at any one time only one person may be talking
(‘transmitting’) to any other one person within the group, this means that the majority of
the group are listening to a single conversation. It rapidly becomes unworkable to have a
tutorial style structure with synchronous interactions, (even when supported by
technology) for more than 8-12 people in a single group. There are two principal reasons
for this: (1) The facilitator cannot monitor and respond appropriately to points being
made in individual conversations. (2) Each conversation takes finite time, therefore there
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