Structural holes
Structural holes is a concept from social network research, originally developed by Ronald Stuart Burt.
A structural hole is understood as a gap between two individuals who have complementary sources to information.
The study of structural holes spans the fields of sociology, economics, and computer science.
Burt introduced this concept in an attempt to explain the origin of differences in social capital.
Burt’s theory suggests that individuals hold certain positional advantages/disadvantages from how they are embedded in neighborhoods or other social structures.
Most social structures tend to be characterized by dense clusters of strong connections, also known as network closure.
[1] An individual who acts as a mediator between two or more closely connected groups of people could gain important comparative advantages.
On contrary, the position of node A makes it serve as a bridge or a ‘broker’ between three different clusters.
As a result of the hole between two contacts, they provide network benefits to the third party (to node A).
Bridge count is a simple and intuitive measure of structural holes in a network.
Bridge is defined as a relation between two individuals if there is no indirect connection between them through mutual contacts.
Borgatti developed a simplified formula to calculate effective size for unweighted networks.
Where t is the number of the total ties in the egocentric network (excluding those ties to the ego) and n is the number of total nodes in the egocentric network (excluding the ego).
This formula can be modified to calculate the effective size of the ego's network.
This indicator measures the extent to which time and energy is concentrated within a single cluster.
It consists of two components: direct, when a contact consumes a large proportion of a network's time and energy, and indirect, when a contact controls other individuals, who consume a large proportion of a network's time and energy.
While Granovetter claims that whether a contact would serve as a bridge depends on a tie’s strength, Burt considers the opposite direction of causality.
Application for this theory can be found in one of Burt's studies of entrepreneurial network.
He studied a network of 673 managers in the supply chain for the firm, and measured the degree of social brokerage.
[1] The findings of this empirical study: There are several practical scenarios related to structural hole-related applications, including enterprise settings, information diffusion in social networks, software development, mobile applications, and machine learning (ML)-based social prediction.
