# wrightMap: item-person maps This function allows the easy generation of `Wright Maps' (named after Ben Wright), also known as item-person maps. They are used to to display unidimensional and multidimensional assessment results. These maps represent simultaneously the proficiency distribution of respondents and the item difficulty parameters as estimated by a model of the Rasch family. ```r wrightMap(thetas, thresholds = NULL, item.side = itemModern, person.side = personHist , main.title = "Wright Map", min.logit.pad = 0.25, max.logit.pad = 0.25, min.l = NULL , max.l = NULL, item.prop = 0.8, return.thresholds = TRUE, new.quartz = FALSE , use.hist = NULL,...) ## S3 method for class 'CQmodel' plot(x, ...) ``` ## Arguments The parameters documented here do not include many of the options included in the Wright Map family of functions. For graphical parameters, see `item.side` and `person.side` . For data handling, see `item.person.data` and `CQmodel` . wrightMap parameters: - `thetas`: a vector, matrix or data frame of person parameter estimates. Can also be a character string specifying a ConQuest output file of person parameter estimates, or a CQmodel object. Will be sent to the function `personData`. - `thresholds`: matrix or data frame of item parameter estimates. Can also be a character string specifying a ConQuest show file. Will be sent to the function `itemData`. - `item.side`: function to use to draw the item side of the map. Currently included options are itemModern (default), itemClassic (for ConQuest-style Wright Maps) and itemHist. See `item.side` for details. - `person.side`: function to use to draw the person side of the map. Currently included options are personHist (default), to draw the person distribution as a histogram, and personDens, which draws a density plot. See `person.side` for details. - `main.title`: title of the Wright Map. - `min.logit.pad`: numeric value indicating how much of the lower end of the logit scale should be included in the plot. - `max.logit.pad`: numeric value indicating how much of the upper end of the logit scale should be included in the plot. - `min.l`: numeric value for fixing the lower end of the logit scale. It overrides the automatic detection of the range and the `min.logit.pad` correction. - `max.l`: numeric value for fixing the upper end of the logit scale. It overrides the automatic detection of the range and the `max.logit.pad` correction. - `item.prop`: numeric value greater than 0 and smaller than 1 indicating the proportion of the plot to be allocated to the item part of the Wright Map. - `return.thresholds`: logical. Determines whether the to return or not the numeric values used to position the parameters on the item side of the Wright Map. Enabled by default. - `new.quartz`: logical. Determines whether the wrightMap will be created on a new graphical device or if it will reuse one already open. By default is set to `FALSE` to avoid creating new devices. - `use.hist`: deprecated. Use the `person.side` parameter instead - ``...``: Additional arguments to pass to `personData`, `itemData`, `person.side`, or `item.side` wrightMap can also be called by passing a CQmodel object to plot: - `x`: CQmodel object to pass to plot ## References Wilson, M. (2005). Constructing measures: An item response modeling approach. Wright, B. D., & Stone, M. H. (1979). **Best test design.** Chicago: Mesa Press. ## Author(s) David Torres Irribarra and Rebecca Freund ## See Also `person.side` `item.side` `personData` `itemData` ## Examples ```r # Plotting results of a unidimensional Rasch Model ## Mock results uni.proficiency <- rnorm(1000, mean = -0.5, sd = 1) difficulties <- sort( rnorm( 20)) ## Default map wrightMap( uni.proficiency, difficulties) ## Density version wrightMap( uni.proficiency, difficulties, person.side = personDens) # Plotting results of a multidimensional Rasch Model ## Mock results multi.proficiency <- data.frame( d1 = rnorm(1000, mean = -0.5, sd = 1), d2 = rnorm(1000, mean = 0.0, sd = 1), d3 = rnorm(1000, mean = +0.5, sd = 1)) difficulties <- sort( rnorm( 20)) dev.new(width=10, height=10) wrightMap( multi.proficiency, difficulties) # Plotting results of a unidimensional Rating Scale Model ## Mock results uni.proficiency <- rnorm(1000, mean = -0.5, sd = 1) items.loc <- sort( rnorm( 20)) thresholds <- data.frame( l1 = items.loc - 0.5 , l2 = items.loc - 0.25, l3 = items.loc + 0.25, l4 = items.loc + 0.5) wrightMap( uni.proficiency, thresholds) ####ConQuest integration### fpath <- system.file("extdata", package="WrightMap") #Partial credit model: model1 <- CQmodel(p.est = file.path(fpath,"ex2.eap"), show = file.path(fpath,"ex2.shw")) wrightMap(model1) # Rating scale model: model2 <- CQmodel(file.path(fpath,"ex2b.eap"), file.path(fpath,"ex2b-2.shw")) wrightMap(model2, label.items.row = 2) # Complex model model3 <- CQmodel(file.path(fpath,"ex4a.mle"), file.path(fpath,"ex4a.shw")) wrightMap(model3, min.logit.pad = -29, person.side = personDens) ### Skip CQmodel wrightMap(file.path(fpath,"ex2a.eap"), file.path(fpath,"ex2a.shw"), label.items.row = 3) ```

wrightMap function