RSiena (version 1.4.7)

varCovar: Function to create a changing covariate object.

Description

This function creates a changing covariate object from a matrix.

Usage

varCovar(val, centered=TRUE, nodeSet="Actors",  warn=TRUE,
  imputationValues=NULL)

Value

Returns the covariate as an object of class "varCovar", in which form it can be used as an argument to sienaDataCreate.

Arguments

val

Matrix of covariate values, one row for each actor, one column for each period.

centered

Boolean: if TRUE, then the overall mean value is subtracted.

nodeSet

Character string containing the name of the associated node set. If the entire data set contains more than one node set, then the node sets must be specified in all data objects.

warn

Logical: is a warning given if all values are NA, or all non-missing values are the same.

imputationValues

Matrix of covariate values of same dimensions as vala, to be used for imputation of NA values (if any) in val. Must not contain any NA.

Author

Ruth Ripley

Details

When part of a Siena data object, the covariate is assumed to be associated with node set nodeSet of the Siena data object. In practice, the node set needs to be specified only in the case of the use of the covariate with a two-mode network.
If there are any NA values in val, and imputationValues is given, then the corresponding elements of imputationValues are used for imputation. If imputationValues is NULL, imputation is by the overall mean value. In both cases, cases with imputed values are not used for calculating target statistics (see the manual).
The value of the changing covariate for wave m is supposed in the simulations to be valid in the whole period from wave m to wave m+1. If the data set has M waves, this means that the values, if any, for wave M will not be used. Therefore, the number of columns can be M or M-1; if the former, the values in the last column will not be used.

References

See https://www.stats.ox.ac.uk/~snijders/siena/

See Also

sienaDataCreate, coCovar, coDyadCovar, varDyadCovar, sienaNodeSet

Examples

myvarCovar <- varCovar(s50a)
senders <- sienaNodeSet(50, nodeSetName="senders")
receivers <- sienaNodeSet(30, nodeSetName="receivers")
senders.covariate <- varCovar(s50a, nodeSet="senders")
receivers.covariate <- varCovar(s50s[1:30,], nodeSet="receivers")