Table 3. Glossary of centralization indexes.

Degree centralization	The extent to which there is asymmetry in the number of direct ties that a node has in a given network (i.e. if some individuals have a disproportionally larger number of knowledge ties than others creating for them a position of prestige).
Betweenness centralization	The extent to which there is asymmetry of influence or control over knowledge in the network (i.e. if some individuals are better positioned as intermediaries in the network than others).
Closeness centralization	The extent to which there is asymmetry in access to knowledge beyond one’s immediate set of contacts (i.e. if some individuals are better able to access information from distant sources whereas others are constrained).
Flow betweenness	The extent to which knowledge can be translated via a range of alternative paths that circumvent the network centre.