An index proposed by Krackhard and Stern (1988) to capture relative prevalence of between- and within-group ties. From that perspective it can be interpreted as a measure of network segregation.
ei(object, ...)# S3 method for table
ei(object, ...)
# S3 method for igraph
ei(
object,
vattr,
directed = is.directed(object),
loops = any(is.loop(object)),
...
)
# S3 method for default
ei(object, ...)
Numerical value of the E-I index.
R object, see Details for available methods
other arguments passed to/from other methods
character scalar or vector of length equal to the size of
object, vertex attribute for which mixing matrix is to be computed
logical whether the network is directed
logical, whether loops are allowed
If object is a table it is interpreted as a mixing matrix.
Two-dimensional table is interpreted as a contact layer. Three-dimensional
table is interpreted as a full mixing matrix \(m_{ghy}\)
cross-classyfying all dyads, in which \(g\) and \(h\) correspond to
group membership of ego and alter respectively. Layers \(y=1\) and
\(y=2\) are assumed to be non-contact and contact layers respectively.
If object is of class "igraph" it is required to supply vattr
with the name of the vertex attribute to calculate intermediate mixing
matrix.
Krackhardt, D., & Stern, R. N. (1988). Informal networks and organizational crises: An experimental simulation. Social Psychology Quarterly, 123-140.
Other segregation measures:
assort(),
coleman(),
freeman(),
gamix(),
orwg(),
smi(),
ssi()