Description Usage Value References See Also Examples
This data set contains materials related to the PooleRosenthal DWNOMINATE measure of senator
ideology. The software (and other materials) is available at ftp://voteview.com/dwnominate.htm,
which includes a simpler example of an application to the 80110 U.S. Senate. The data set here is
derived from the data and estimates from that example, but are formatted to be run in hierIRT()
.
In particular, start values for estimation are identical to those provided by the example.
1 
dwnom 
list, containing the following elements:

DWNOMINATE is described in Keith T. Poole and Howard Rosenthal. 1997. Congress: A Political Economic History of Roll Call Voting. Oxford University Press. See also ftp://voteview.com/dwnominate.htm.
Variational model is described in 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.
'hierIRT'.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  ### Real data example of US Senate 80110 (not run)
### Based on voteview.com example of DWNOMINATE (ftp://voteview.com/dwnominate.htm)
### We estimate a hierarchical model without noise and a linear time covariate
### This model corresponds very closely to the DWNOMINATE model
## Not run:
data(dwnom)
## This takes about 10 minutes to run on 8 threads
## You may need to reduce threads depending on what your machine can support
lout < hierIRT(.data = dwnom$data.in,
.starts = dwnom$cur,
.priors = dwnom$priors,
.control = {list(
threads = 8,
verbose = TRUE,
thresh = 1e4,
maxit=200,
checkfreq=1
)})
## Bind ideal point estimates back to legislator data
final < cbind(dwnom$legis, idealpt.hier=lout$means$x_implied)
## These are estimates from DWNOMINATE as given on the Voteview example
## From file "SL80110C21.DAT"
nomres < dwnom$nomres
## Merge the DWNOMINATE estimates to model results by legislator ID
## Check correlation between hierIRT() and DWNOMINATE scores
res < merge(final, nomres, by=c("senate","id"),all.x=TRUE,all.y=FALSE)
cor(res$idealpt.hier, res$dwnom1d)
## End(Not run)

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