convertRC {emIRT}

Convert Roll Call Matrix Format

Description

convertRC takes a rollcall object and converts it into a format suitable for estimation with 'binIRT'.

Usage

  convertRC(.rc, type = "binIRT") 

Arguments

.rc

a rollcall object containing votes to be scaled using 'binIRT'.

type

string, only “binIRT” is supported for now, and argument is ignored.

Value

An object of class rollcall, with votes recoded such that yea=1, nay=-1, missing data = 0.

Author(s)

Kosuke Imai [e-mail]

James Lo [e-mail]

Jonathan Olmsted [e-mail]

References

Kosuke Imai, James Lo, and Jonathan Olmsted “Fast Estimation of Ideal Points with Massive Data.” Working Paper. Available at http://imai.princeton.edu/research/fastideal.html.

See Also

'binIRT', 'makePriors', 'getStarts'.

Examples

## Data from 109th US Senate
data(s109)

## Convert data and make starts/priors for estimation
rc <- convertRC(s109)
p <- makePriors(rc$n, rc$m, 1)
s <- getStarts(rc$n, rc$m, 1)

## Conduct estimates
lout <- binIRT(.rc = rc,
                .starts = s,
                .priors = p,
                .control = {
                    list(threads = 1,
                         verbose = FALSE,
                         thresh = 1e-6
                         )
                }
                )

## Look at first 10 ideal point estimates
lout$means$x[1:10]