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258 Selected Studies on Software and Information Systems
(Backstrom, 2006) analyzed the evolution and growth of communities on huge Live-
Journal community of more than 10 million users with a significant fraction of the users
being very active with about 300,000 profile updates in 24-hour period, and arrived at an
interesting observation that not only the number of existing ties – friends that are already
members – determines the probability of joining the community but also by how these
friends are connected to one another with strong ties between these friends to be more
favorable.
If the groups are not yet established they can be created trivially either randomly or
self-selected by students according to learner profiles. Another way is to use computersupported
approaches. The research on algorithms for creating groups seems to divide
into two principally different strands:
1. One-time formation methods produce a single assignment of participants into groups
according to pre-defined criteria. Groups are created in this process only once and
thus it cannot possibly take future collaboration outputs into account during
the group creation process. Different methods of this type are used:
a. constraint-based, where the allocation problem is expressed as a Constraint Satisfaction
Problem (Kumar, 1992) and the negotiation problem can then be handled by
a constrain satisfaction solver,
b. statistical methods which represent students’ features using a vector-based approach
and generate assignments into groups employing various statistical or optimization
algorithms.
2. Repeated formation methods assume that multiple rounds of collaboration will happen
and take feedback on previous assignments into account during the creation of next
assignment of students into groups. In effect, these methods are self-optimizing as the
creation process is set up in such a way that the benefits of the current allocation are
evaluated after the collaboration completes and further reused, thus rewarding a better
allocation next time.
The actual process of setting up an individual group is usually a three stage process
(Wessner, 2001): (1) initiating the formation manually by the learner or triggered automatically
by the system, (2) identifying peer learners that meet certain requirements, and (3)
negotiating with potential participants.
Collaborative tasks are often executed in a structured way and involve a certain
amount of role-playing which further imposes skill and ability demands on possible actors.
Demands for different roles are usually different so that even actors with sharply
contrasting skill sets may find the collaborative experience of working together rewarding.
For example, in an early collaborative effort, the COSOFT project (Hoppe, 1995) when
the learner encounters a problem he (phase 1) initiates the formation of a so-called learnerhelper
group by pressing the “Ask” button. System displays a list of potential peers (phase
2) based on the learner model. The learner can then select the helper who is subsequently
asked if she wishes to help the learner with the current topic (phase 3). After this learnerhelper
group is successfully negotiated a shared communication channel between them is
established.
In OurWeb system (Miettinen, 2005), group formation is supported by identifying
students with shared interests; authors suggest that a suitable way of supporting group