R: Nodal attribute-based homophily effect for the first mode in...

b1nodematch-ergmTerm {ergm} | R Documentation

## Nodal attribute-based homophily effect for the first mode in a bipartite network

### Description

This term is introduced in Bomiriya et al (2014). With the default `alpha` and `beta` values, this term will simply be a homophily based two-star statistic. This term adds one statistic to the model unless `diff` is set to `TRUE` , in which case the term adds multiple network statistics to the model, one for each of (a subset of) the unique values of the `attr` attribute.

### Usage

    # binary: b1nodematch(attr, diff=FALSE, keep=NULL, alpha=1, beta=1, byb2attr=NULL,
    #                     levels=NULL)

### Arguments

`attr` | quantitative attribute (see Specifying Vertex attributes and Levels (`?nodal_attributes`) for details.)
`diff` | by default, one statistic will be added to the model. If `diff` is set to `TRUE`, one statistic will be added for each unique value of the `attr` attribute
`keep` | deprecated
`alpha, beta` | optional discount parameters both of which take values from `[0, 1]`, only one should be set at one time
`byb2attr` | specifies a second mode categorical attribute. Setting this argument will separate the orginal statistics based on the values of the set second mode attribute— i.e. for example, if `diff` is `FALSE` , then the sum of all the statistics for each level of this second-mode attribute will be equal to the original `b1nodematch` statistic where `byb2attr` set to `NULL` .
`levels` | select a subset of `attr` values to include. (See Specifying Vertex attributes and Levels (`?nodal_attributes`) for details.)

### Details

If an `alpha` discount parameter is used, each of these statistics gives the sum of the number of common second-mode nodes raised to the power `alpha` for each pair of first-mode nodes with that attribute. If a `beta` discount parameter is used, each of these statistics gives half the sum of the number of two-paths with two first-mode nodes with that attribute as the two ends of the two path raised to the power `beta` for each edge in the network.

### Note

This term can only be used with undirected bipartite networks.

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 Also

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

[Package ergm version 4.2.2 Index]