`nwego`

Ego-network size and density

Syntax

nwego
[netlist]
[,
sizevar(newvarname)
densvar(newvarname)
replace
silent]


`sizevar(newvarname)`	Required. Name of the Stata variable that stores ego-network size
`densvar(newvarname)`	Required. Name of the Stata variable that stores ego-network density
`replace`	Replace existing variables
`silent`	Suppress display of results

Description

nwego calculates, for every node, the size and density of its ego network. A node’s alters are every other node it has any tie with - for a directed network, the union of its incoming and outgoing ties (the standard “who is in ego’s network at all” question; this is distinct from nwaltergen’s own alter-aggregation convention, which deliberately keeps incoming and outgoing ties separate for a different purpose).

Ego-network size is simply the number of alters (equivalent to nwdegree for an undirected network; for a directed network it is the count of distinct nodes tied in either direction, not the sum of in- and out-degree, which could double-count a reciprocated tie).

Ego-network density is the proportion of possible ties actually present among the alters themselves - ego itself is excluded, the standard convention for reporting how interconnected an ego’s contacts are with each other, independent of their (by definition, complete) ties to ego. For a directed network, ordered alter-alter pairs are counted (an alter set of size k has k(k-1) possible ties); for an undirected network, unordered pairs are counted (k(k-1)/2 possible ties). An ego with fewer than 2 alters has no pair to assess - density is reported missing for it, not spuriously 0 or 1.

sizevar() and densvar() are both required and name the Stata variables that store ego-network size and density, respectively.

Examples

. nwwebuse florentine, nwclear
. nwego flomarriage, sizevar(_egosize) densvar(_egodensity)

Supported network types

Binary: yes. Directed: yes - alters are the union of in- and out-neighbors; alter-alter density counts ordered pairs. Weighted: not used - only presence/absence of a tie determines ego-network membership and alter-alter density; tie strength does not affect these measures. Signed: not checked. Two-mode: not checked - operates on the network’s own square adjacency matrix.

References

Burt, R.S. (1992). Structural Holes: The Social Structure of Competition. Harvard University Press. (ego-network density as used in structural holes analysis - see also nwconstraint, nwburt)

nwego