nodematch-ergmTerm-b316dba4: Uniform homophily and differential homophily

In ergm: Fit, Simulate and Diagnose Exponential-Family Models for Networks

Uniform homophily and differential homophily

Description

When diff=FALSE , this term adds one network statistic to the model, which counts the number of edges (i,j) for which attr(i)==attr(j) . This is also called “uniform homophily”, because each group is assumed to have the same propensity for within-group ties. When multiple attribute names are given, the statistic counts only ties for which all of the attributes match. When diff=TRUE , p network statistics are added to the model, where p is the number of unique values of the attr attribute. The k th such statistic counts the number of edges (i,j) for which ⁠attr(i) == attr(j) == value(k)⁠ , where value(k) is the k th smallest unique value of the attr attribute. This is also called “differential homophily”, because each group is allowed to have a unique propensity for within-group ties. Note that a statistical test of uniform vs. differential homophily should be conducted using the ANOVA function.

By default, matches on all levels k are counted. This works for both diff=TRUE and diff=FALSE .

Usage

# binary: nodematch(attr, diff=FALSE, keep=NULL, levels=NULL)

# valued: nodematch(attr, diff=FALSE, keep=NULL, levels=NULL, form="sum")

# valued: match(attr, diff=FALSE, keep=NULL, levels=NULL, form="sum")

Arguments

attr	a vertex attribute specification (see Specifying Vertex attributes and Levels (?nodal_attributes) for details.)
diff	specify if the term has uniform or differential homophily
keep	deprecated
levels	this optional argument controls which levels of the attribute should be included and which should be excluded. (See Specifying Vertex attributes and Levels (?nodal_attributes) for details.)
form	how to aggregate tie values in a valued ERGM: "sum" (the default) for a statistic of the form \sum_{i,j} x_{i,j} y_{i,j}, where y_{i,j} is the value of dyad (i,j) and x_{i,j} is the term's covariate associated with it; and "nonzero" with the edge considered to be present if its value is not 0. See ergmTerm for more information.

Note

The argument keep is retained for backwards compatibility and may be removed in a future version. When both keep and levels are passed, levels overrides keep. See nodal_attributes.

See Also

ergmTerm for index of model terms currently visible to the package.

\Sexpr[results=rd,stage=render]{ergm:::.formatTermKeywords("ergmTerm", "nodematch", "subsection")}

ergm documentation built on Feb. 18, 2026, 1:06 a.m.