vectorRepresentation: convert roll call matrix to series of vectors

Description

Extract the information in a roll call matrix as a series of vectors with voting decision, a unique identifier for the legislator and a unique identifier for the roll call.

Usage

vectorRepresentation(object, dropList = list(codes = c("missing", "notInLegis")))

Arguments

object

an object of class rollcall

dropList

a dropList; see dropRollCall

Value

A matrix with z rows, where z is the number of non-missing entries in object$votes, with missingness defined by the codes component of the dropList. The matrix has 3 columns:
votethe voting decision, either a 1 if the corresponding element of the roll call matrix object$votes is in the yea component of object$codes, or a 0 if the corresponding element of the roll call matrix is in the nay component of object$codes. Non-missing entries of the roll call matrix are not stored.
ithe row of the roll call matrix object$votes that supplied the voting decision; i.e., a unique identifier for the legislator generating this vote
jthe column of the roll call matrix object$votes that supplied the vote; i.e., a unique identifier for the vote.

Details

It is often the case that roll call matrices are sparse, say, when the roll call matrix has an overlapping generations structure, pooling across many legislatures such that few of the represented legislators actually vote on any given roll call. In such a case, representing the data as a roll call matrix is not particularly helpful, either for data summaries or modeling.

Examples

Run this code

data(s109)
y <- vectorRepresentation(s109)
apply(y,2,table,exclude=NULL)