plotPWmap | R Documentation |
A Bond-and-Fox Pathway Map displays the location of each item or each person against its infit t-statistic. Pathway maps are useful for identifying misfitting items or misfitting persons. Items or people should ideally have a infit t-statistic lying between about -2 and +2, and these values are marked.
plotPWmap(object, pmap = FALSE, imap=TRUE,
item.subset = "all", person.subset = "all",
mainitem = "Item Map", mainperson = "Person Map",
mainboth="Item/Person Map",
latdim = "Latent Dimension",
tlab = "Infit t statistic",
pp = NULL, cex.gen = 0.6, cex.pch=1,
person.pch = 1, item.pch = 16,
personCI = NULL, itemCI = NULL, horiz=FALSE)
object |
Object of class |
pmap |
Plot a person map if |
imap |
Plot an item map if |
item.subset |
Subset of items to be plotted for an item map.
Either a numeric vector indicating the item numbers or a character
vector indicating the item names. If |
person.subset |
Subset of persons to be plotted for a person map.
Either a numeric vector indicating the person numbers or a character
vector indicating the person names. If |
mainitem |
Main title of an item plot. |
mainperson |
Main title of a person plot. |
mainboth |
Main title of a person/item joint plot. |
latdim |
Label of the y-axis, i.e., the latent dimension. |
tlab |
Label of the x-axis, i.e., the t-statistic dimension. |
pp |
If non- |
cex.gen |
|
cex.pch |
applies to all plotting symbols. The default is 1. |
person.pch , item.pch |
Specifies the symbol used for plotting
person data and item data respectively; the defaults are 1 and 16
respectively. See |
personCI , itemCI |
Plotting confidence intervals for the the
person abilities and item difficulties. If The same goes for |
horiz |
if |
This code uses vertical(horizontal) error bars rather than circles or boxes to indicate standard errors. It also offers the possibility of plotting item or person data on its own; this can considerably simplify the reading of the plots for large datasets.
Julian Gilbey
Bond T.G., Fox C.M. (2007) Applying the Rasch Model: Fundamental Measurement in the Human Sciences (2nd ed.) chapter 3, Lawrence Erlbaum Associates, Inc.
Linacre J.M., Wright B.D. (1994) Dichotomous Infit and Outfit Mean-Square Fit Statistics / Chi-Square Fit Statistics. Rasch Measurement Transactions 8:2 p. 350, https://www.rasch.org/rmt/rmt82a.htm
Linacre J.M. (2002) What do Infit and Outfit, Mean-square and Standardized mean? Rasch Measurement Transactions 16:2 p. 878, https://www.rasch.org/rmt/rmt162f.htm
Wright B.D., Masters G.N. (1990) Computation of OUTFIT and INFIT Statistics. Rasch Measurement Transactions 3:4 p. 84–85, https://www.rasch.org/rmt/rmt34e.htm
res <- PCM(pcmdat)
pparm <- person.parameter(res)
plotPWmap(res, pp = pparm)
plotPWmap(res, pp = pparm, pmap = TRUE)
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