LC1980_bbt: Blackbox Transpose Estimate, 1980 Liberal-Conservative...
In basicspace: Recovering a Basic Space from Issue Scales

Description Usage Value Author(s) Source See Also Examples

Blackbox-Transpose estimates from Liberal-Conservative 7-point scales from the 1980 National Election Study. Estimates in 3 dimensions.

1	data(LC1980_bbt)

An object of class blackbt.

stimuli

vector of data frames of length dims. Each data frame presents results for estimates from that dimension (i.e. x$stimuli[[2]] presents results for dimension 2). Each row contains data on a separate stimulus, and each data frame includes the following variables:

NNumber of respondents who ranked this stimulus.
coord1DLocation of the stimulus in the first dimension. If viewing the results for a higher dimension, higher dimension results will appear as coord2D, coord3D, etc.
R2The percent variance explained for the stimulus. This increases as more dimensions are estimated.

individuals

vector of data frames of length dims. Each data frame presents results for estimates from that dimension (i.e. x$stimuli[[2]] presents results for dimension 2). Individuals that are discarded from analysis due to the minscale constraint are NA'd out. Each row contains data on a separate stimulus, and each data frame includes the following variables:

cEstimate of the individual intercept.
w1Estimate of the individual slope. If viewing the results for a higher dimension, higher dimension results will appear as w2, w3, etc.
R2The percent variance explained for the respondent. This increases as more dimensions are estimated.

fits

A data frame of fit results, with elements listed as follows:

SSESum of squared errors.
SSE.explainedExplained sum of squared error.
percentPercentage of total variance explained.
SEStandard error of the estimate, with formula provided in the article cited below.
singularSingluar value for the dimension.

`Nrow`	Number of rows/stimuli.
`Ncol`	Number of columns used in estimation. This may differ from the data set due to columns discarded due to the minscale constraint.
`Ndata`	Total number of data entries.
`Nmiss`	Number of missing entries.
`SS_mean`	Sum of squares grand mean.
`dims`	Number of dimensions estimated.

Keith Poole ktpoole@uga.edu

Howard Rosenthal hr31@nyu.edu

Jeffrey Lewis jblewis@ucla.edu

James Lo lojames@usc.edu

Royce Carroll rcarroll@rice.edu

American national Election Study. http://www.electionstudies.org/

'plotcdf.blackbt', 'LC1980', 'plot.blackbt', 'summary.blackbt', 'blackbox_transpose'.

### Loads and scales the Liberal-Conservative scales from the 1980 NES.
data(LC1980)
LCdat=LC1980[,-1]	#Dump the column of self-placements


### This command conducts estimates, which we instead load using data()

#LC1980_bbt <- blackbox_transpose(LCdat,missing=c(0,8,9),dims=3,minscale=5,verbose=TRUE)
data(LC1980_bbt)

plot(LC1980_bbt)
par(ask=TRUE)
plotcdf.blackbt(LC1980_bbt)
summary(LC1980_bbt)