RSiena (version 1.4.7)

sienaCompositionChange: Functions to create a Siena composition change object

Description

Used to create a list of events describing the changes over time of a Siena actor set.

Usage

sienaCompositionChange(changelist, nodeSet = "Actors", option = 1)
sienaCompositionChangeFromFile(filename, nodeSet = "Actors",
    fileobj=NULL, option = 1)

Value

An object of class "compositionChange", a list of numeric vectors, with attributes:

NodeSet

Name of node set

Option

Option

Arguments

changelist

A list with an entry for each actor in the node set. Each entry a vector of numbers (may be as characters) indicating intervals during which the corresponding actor was present. Each entry must have an even number of digits. The actor is assumed to be present from the first to the second, third to fourth, etc., time points.

filename

Name of file containing change information. One line per actor, each line a series of space delimited numbers indicating intervals.

fileobj

The result of readLines on filename.

nodeSet

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

option

Integer controlling the processing of the tie variables for the actors not currently present. Values (default is 1)

1	0 before entry, final value carried forward after leaving,
	and used for calculating statistics in Method of Moments estimation
2	0 before entry, missing after (final value carried forward, but treated as missing)
3	missing whenever not in the network. Previous values will be used where available,
	but always treated as missing values.
4	Convert to structural zeros (not available at present).

Author

Ruth Ripley

Details

If there is a composition change object for the first node set in the data object, then this will be used in estimation by the Method of Moments to make actors active (able to send and receive ties) only for the time intervals when this is indicated in the composition change object. This is done according to the procedure of Huisman and Snijders (2003). See the manual for further details.
For bipartite networks, composition change objects for the second node set have no effect and will lead to an error message.
For M waves, time starts at 1 and ends at M; so all numbers must be between 1 and the number of waves (bounds included). Intervals are treated as closed at each end. For example, an entry (2, 4) means that the actor corresponding to this entry arrived at wave 2 and left at wave 4, but did give valid date for both of these waves. An entry (1.01, 2.99) means that the actor arrived just after wave 1 and left just before wave 3, and gave valid data only for wave 2. An entry (1, 2), (3.5, 4) means that the actor was there at the start and left at wave 2 (giving valid data for wave 2), came back halfway between waves 3 and 4, and gave valid data still at wave 4; if there would be more than 4 waves in the data set, this entry would also mean that the actor left at wave 4.
For data sets including a composition change object, estimation by Method of Moments is forced to be unconditional, overriding the specification in the sienaAlgorithm object.

References

Huisman, M.E. and Snijders, T.A.B. (2003), Statistical analysis of longitudinal network data with changing composition. Sociological Methods & Research, 32, 253--287.

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

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

See Also

sienaNodeSet, sienaDataCreate

Examples

  clist <- list(c(1, 3), c(1.4, 2.5))
  #or
  clist <- list(c("1", "3"), c("1.4", "2.5"))

  compChange <- sienaCompositionChange(clist)

  s50net <- sienaDependent(array(c(s501, s502, s503), dim=c(50, 50, 3)))
  s50list <- rep(list(c(1,3)), 50)
  # This is a trivial composition change: all actors are present in all waves.
  compChange <- sienaCompositionChange(s50list)
  s50data <- sienaDataCreate(s50net, compChange)
  s50data

  if (FALSE) {
  filedata <- c("1 3", "1.4 2.5")
  write.table(filedata, "cc.dat",row.names=FALSE, col.names=FALSE,
          quote=FALSE)
  ## file will be
  ## 1 3
  ## 1.4 2.5
  compChange <- sienaCompositionChangeFromFile("cc.dat")
  }