Keystone sector methodology applied to Portugal
In a social network, bigger is not always better. Increasing the network size
without considering its diversity can very often affect the quality of the social network.
If added contacts lead each node to the same people they can become redundant, which
means costly. A very dense network could be considered inefficient in the way that it
returns less diverse information with a higher cost than a less dense but diversified
network. Measuring the effort/time needed to add a new contact as an additional cost,
one actor is inefficient if the new contact leads to a similar existent contact. It is
considered as a redundancy while it only adds cost against no added gain.
To find such structural holes, empirical indicators - cohesion or structural
equivalence - are used. Two contacts are redundant “to the extent that they are
connected by a strong relationship ” (husband and wife will constitute a redundancy to
the set of a third person contacts). Two people are said to be structural equivalent “ to
the extent that they have the same contacts” (knowing one or two ministers in the same
Government). Usually cohesion is the criterion to find direct contacts and structural
equivalence is appropriate to find indirect contacts. Although they are important
indicators, they are neither absolute nor independent. When jointly considered,
redundancy is most likely to occur between structurally equivalent people connected by
a strong relationship rather than between total strangers in distant groups.
Under this perspective, balancing network size is a question of optimizing
structural holes. It is reasonable to predict that the number of structural holes will rise
with the network size, so it is important to consider the two design principles behind the
optimal network: efficiency and effectiveness.
These principles are represented in figure 1, extracted from Burt (1992: 24):
N. of contacts (Network size)