nodefactor-ergmTerm {ergm}

Factor attribute effect

Description

This term adds multiple network statistics to the model, one for each of (a subset of) the unique values of the attr attribute (or each combination of the attributes given). Each of these statistics gives the number of times a node with that attribute or those attributes appears in an edge in the network.

Usage

# binary: nodefactor(attr, base=1, levels=-1)

# valued: nodefactor(attr, base=1, levels=-1, form="sum")

Arguments

attr

a vertex attribute specification (see Specifying Vertex attributes and Levels (?nodal_attributes) for details.)

base

deprecated

levels

this optional argument controls which levels of the attribute attributes and Levels (?nodal_attributes) for details.)

form

character how to aggregate tie values in a valued ERGM

Note

To include all attribute values is usually not a good idea, because the sum of all such statistics equals the number of edges and hence a linear dependency would arise in any model also including edges. The default, levels=-1, is therefore to omit the first (in lexicographic order) attribute level. To include all levels, pass either levels=TRUE (i.e., keep all levels) or levels=NULL (i.e., do not filter levels).

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

See Also

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

Keywords

categorical nodal attribute, directed, dyad-independent, frequently-used, undirected, binary, valued