rollcall {pscl} | R Documentation |
Create a rollcall
object, used for the analysis of legislative
voting or, equivalently, item-response modeling of binary data
produced by standardized tests, etc.
rollcall(data, yea=1, nay=0, missing=NA, notInLegis=9, legis.names=NULL, vote.names=NULL, legis.data=NULL, vote.data=NULL, desc=NULL, source=NULL)
data |
voting decisions (for roll calls), or test results (for
IRT). Can be in one of two forms. First, data may be a
matrix , with rows corresponding to legislators
(subjects) and columns to roll calls (test items). data can
also be a list with an element named votes
containing the matrix described above. |
yea |
numeric, possibly a vector, code(s) for a Yea vote in the rollcall context, or a correct answer in the educational testing context. Default is 1. |
nay |
numeric, possibly a vector, code(s) for a Nay vote in the rollcall context, or an incorrect answer in the educational testing context. Default is 0. |
missing |
numeric or NA , possibly a vector, code(s) for
missing data. Default is NA . |
notInLegis |
numeric or NA , possibly a vector, code(s) for
the legislator not being in the legislature when a particular roll
call was recorded (e.g., deceased, retired, yet to be elected). |
legis.names |
a vector of names of the legislators or
individuals. If data is a list or data.frame
and has a component named legis.names , then this will be
used. Names will be generated if not supplied, or if there are
fewer unique names supplied than legislators/subjects (rows of the
roll call matrix). |
vote.names |
a vector of names or labels for the votes or items.
If data is a list or data.frame and has a
component named vote.names , then this will be used. Names
will be generated if not supplied, or if there are fewer unique
names supplied than votes/test-items (columns of the roll call
matrix). |
legis.data |
a matrix or data.frame
containing covariates specific to each legislator/test-taker; e.g.,
party affiliation, district-level covariates. If this object does
not have the same number of rows as data , an error is
returned. |
vote.data |
a matrix or data.frame
containing covariates specific to each roll call vote or test item;
e.g., a timestamp, the bill sponsor, descriptive text indicating
the type of vote. If this object does not have the same number of
row as the number of columns in data , an error is returned. |
desc |
character, a string providing an (optional) description of
the data being used. If data is a list and contains an
element named desc , then this will be used. |
source |
character, a string providing an (optional) description of where the roll call data originated (e.g., a URL or a short-form reference). Used in print and summary methods. |
See below for methods that operate on objects of class
rollcall
.
An object of class rollcall
, a list with the following components:
votes |
a matrix containing voting decisions, with
rows corresponding to legislators (test subjects) and columns to
roll call votes (test items). Legislators (test subjects)
and items (or votes) have been labeled in the
dimnames attribute of this matrix, using
the legis.names and/or vote.names arguments, respectively. |
codes |
a list with named components yea ,
nay , notInLegis and missing , each component a
numeric vector (possibly of length 1 and possibly NA ),
indicating how entries in the votes component of the
rollcall object should be considered. This list simply gathers
up the values in the yea , nay , notInLegis and
missing arguments passed to the function. |
n |
numeric, number of legislators, equal to dim(votes)[1] |
m |
numeric, number of votes, equal to dim(votes)[2] |
legis.data |
user-supplied data on legislators/test-subjects. |
vote.data |
user-supplied data on rollcall votes/test-items. |
desc |
any user-supplied description. If no description was provided,
defaults desc defaults to NULL . |
source |
any user-supplied source information (e.g., a url or a
short-form reference). If no description is provided, source
defaults to NULL . |
readKH
for creating objects from files (possibly over
the web), in the format used for data from the United States Congress
used by Keith Poole and Howard Rosenthal (and others).
summary.rollcall
, ideal
for model fitting.
## generate some fake roll call data set.seed(314159265) fakeData <- matrix(sample(x=c(0,1),size=5000,replace=TRUE), 50,100) rc <- rollcall(fakeData) is(rc,"rollcall") ## TRUE rc ## print the rollcall object on screen data(sc9497) ## Supreme Court example data rc <- rollcall(data=sc9497$votes, legis.names=sc9497$legis.names, desc=sc9497$desc) summary(rc,verbose=TRUE) ## Not run: ## s107 ## could use readKH for this dat <- readLines("sen107kh.ord") dat <- substring(dat,37) mat <- matrix(NA,ncol=nchar(dat[1]),nrow=length(dat)) for(i in 1:103){ mat[i,] <- as.numeric(unlist(strsplit(dat[i], split=character(0)))) } s107 <- rollcall(mat, yea=c(1,2,3), nay=c(4,5,6), missing=c(7,8,9), notInLegis=0, desc="107th U.S. Senate", source="http://voteview.ucsd.edu") summary(s107) ## End(Not run)