plot.mdf: 'plot' function for 'mdf' class objects.

In SpyrosBalafas/mudfold: Multiple UniDimensional unFOLDing

Description

Generic function for plotting S3 class mdf objects. This function, is plotting the rows of the conditional adjacency matrix (CAM) which are nonparametric estimates of the item response functions. The plot is produced using the ggplot function from the package ggplot2.

Usage

## S3 method for class 'mdf'
plot(x,select=NULL,plot.type="IRF",...)

Arguments

x	Object of class mdf
select	: in this argument we can provide a subset of items that we wish them to be explicitly plotted. If select=NULL the estimated IRF for each item in the scale is plotted.
plot.type	: Determines the type of plot that is returned. By default, plot.type="IRF", which returns the estimated IRFs for the MUDFOLD item order. The user can set plot.type="scale" in order to get plotted the unidimensional MUDFOLD scale.
...	Other arguments passed on to ggplot plotting method.

Details

The plot method is used to obtain a graphical representation of the estimated item response functions. As estimates of the IRFs are considered the rows of the CAM. For interpolating the missing diagonal elements of the CAM, we make use of the na.approx function from the package zoo.

Author(s)

Spyros E. Balafas (auth.), Wim P. Krijnen (auth.), Wendy J. Post (contr.), Ernst C. Wit (auth.)

Maintainer: Spyros E. Balafas ([e-mail])

References

W.H. Van Schuur.(1984). Structure in Political Beliefs: A New Model for Stochastic Unfolding with Application to European Party Activists. CT Press.

W.J. Post. (1992). Nonparametric Unfolding Models: A Latent Structure Approach. M & T series. DSWO Press.

W.J. Post and T.AB. Snijders. (1993).Nonparametric unfolding models for dichotomous data. Methodika.

A. Zeileis and G. Grothendieck. (2005). zoo: S3 Infrastructure for Regular and Irregular Time Series. Journal of Statistical Software, 14(6), 1-27. doi:10.18637/jss.v014.i06

H. Wickham. (2009). ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York.

H. Wickham. (2007). Reshaping Data with the reshape Package. Journal of Statistical Software, 21(12), 1-20. URL http://www.jstatsoft.org/v21/i12/.

Examples

## Not run: 
data(ANDRICH)
fit <- mudfold(ANDRICH)
plot(fit)
plot(fit,select="DONTBELIEV")

## End(Not run)

SpyrosBalafas/mudfold documentation built on May 19, 2019, 2:53 a.m.