R: plot methods for predictions from ideal objects

plot.predict.ideal {pscl} | R Documentation

## plot methods for predictions from ideal objects

### Description

Plot classification success rates by legislators, or by roll calls, using predictions from ideal.

### Usage

    ## S3 method for class 'predict.ideal'
    plot(x, type = c("legis", "votes"),...)

### Arguments

`x` | an object of class `predict.ideal`.
`type` | string; one of `legis` or `votes`.
`...` | further arguments passed to or from other methods.

### Details

`type="legis"` produces a plot of the “percent correctly predicted” for each legislator/subject (using the classification threshold set in `predict.ideal`) against the estimated ideal point of each legislator/subject (the estimated mean of the posterior density of the ideal point), dimension at a time. If the legislators' party affiliations are availble in the `rollcall` object that was passed to `ideal`, then legislators from the same party are plotted with a unique color.

`type="votes"` produces a plot of classification rates for each roll call, by the percentage of legislators voting for the losing side. The `x`-ordinate is jittered for clarity.

### Value

After drawing plots on the current device, exits silently returning `invisible(NULL)`.

### Author(s)

Simon Jackman simon.jackman@sydney.edu.au

### See Also

`predict.ideal` `ideal`

### Examples

    data(s109)
    f = system.file("extdata","id1.rda",package="pscl")
    load(f)
    phat <- predict(id1)
    plot(phat,type="legis")
    plot(phat,type="votes")

[Package pscl version 1.5.2 Index]