The third measure of centrality, called betweenness centrality, is used to highlight central members that potentially have some control over interactions with other nonadjacent members by lying on the path between the two (Wasserman & Faust, 1994, p. 189). This measure indicates the amount of information that is routed through a central member, sometimes called brokering, which indicates that an individual would be involved in many discussions within the network (Haythornthwaite, 1996; Chinowsky et al., 2010).
Brass (1984) found that closeness and betweenness centrality corresponded to the two necessary conditions related to acquiring power: decreasing dependence on others through increasing an actor’s independent access to resources (closeness centrality) and increasing other’s dependence on the actor which increases control (betweenness centrality). This means that central actors have access to and control over resources that decrease their dependence on others and increase others’ dependence on them (Brass, Galaskiewicz, Greve, & Tsai, 2004). The closeness measure is therefore representative of access to sources of power and the betweenness measure is representative of control of sources of power (Brass, 1984).
distinguish sources of power that are available to central actors (Ibarra & Andrews, 1993). Social network theory distinguishes between workflow, also called instrumental, network links formed through work roles and expressive networks which primarily provide friendship and social support (Brass, 1984; Krackhardt, 1990; Ibarra & Andrews, 1993).
2.8.1 Workflow network
The workflow network is the basis for interaction through the recurring exchange of inputs and outputs between workers based on their role or position within an organisation (Brass, 1984). The source of power derives from the position that the individual holds which makes them critical in a project network when they are in a focal position and there are no alternatives available (Brass, 1984).
The workflow network is a source of power and information because it provides resources such as physical, financial, human or other types of resources to the project (Smith-Doerr et al., 2004). Central actors in workflow network will gain influence as their access to and control over resources increases because they are able to exchange a multitude of resources required by others (Ibarra, 1993; Brass, 1984).
Assudani and Kloppenborg (2010) indicate that salient project stakeholders could be identified by finding out who was being asked for input into the project which
would measure their centrality in the workflow network. Krackhardt (1990) found evidence that individuals in an organisation who had more cognition of the advice network (which represented the workflow network in the study) were more central to the network and were rated as more powerful by others.
Formal position that allows individuals to access or control resources has been classified by Yukl (1998) as positional power. Project work is structured around the work roles that have to be performed by key stakeholders in critical roles.
Therefore, it could be expected that important project stakeholders derive power from their position in the workflow network.
2.8.2 Friendship network
The friendship network is also sometimes called the ―primary network‖ and captures important effective social bonds related to trust (Krackhardt, 1990). It links employees together based on the social liking or friendship which provides a good measure of the informal structure of an organisation (Brass, 1984). Individuals typically express liking and friendship to others that have similar organisational affiliations, personal characteristics and similar interests (Ibarra & Andrews, 1993).
Brass (1984) concluded that friendship was not directly related to power but that friendship connections are vital in obtaining access to resources such as information or rewards. Krackhardt (1990) found that accurate cognitions of certain networks could be a source of power in itself. He argued that knowing who was
central in a given network is ―essential political knowledge‖ and that this information could be used to identify coalitions (Krackhardt, 1990).
Individuals in central positions in friendship networks are expected to be highly influential and interconnected individuals that can form strong coalitions (Brass, 1984). Central actors in the friendship network will have access to and control over sources of power based on their reputation and charisma (Krackhardt, 1990).
Coalition and alliance formation power form part of Yukl’s (1998) definition of political power so it is reasonable that individuals should be important project stakeholders because of their political power in the friendship network.
2.8.3 Communication network
Assudani and Kloppenborg (2010) also suggested that communication networks could be used to identify salient stakeholders based on who individuals frequently talk to about project-related activities. The communication network is based on the exchange of information (Brass, 1984). Communication networks can be examined to determine the informal network that exists within a project team (Chinowsky et al., 2008). Stakeholders will use the communication network to provide information on their critical claims and demand immediate action (Aaltonen et al., 2008) and address conformance gaps in the project (El-Sheikh & Pryke, 2010).
Influence and power have been correlated to communication network centrality in small decision-making groups (Pryke, 2004) and central actors in the communication network have been found to be more influential in organisations (Brass, 1984). Yukl (1998) defined information referent and expert power as a form of personal power which means that important project stakeholders should be central actors in the communication network.