The CQmodel function reads ConQuest item parameter and person parameter output files and converts them into a list of data frames for more convenient data processing.
This function takes as its input a CQmodel object or the name of a ConQuest show file. It adds together the parameters as specified by the user, or if no tables are specified it reads the model equation to determine the appropriate tables to sum. This function is used by wrightMap to draw the item side of the map when a CQmodel is passed to wrightMap.
The plotCI function is intended for graphing confidence intervals. The difplot function is a wrapper for plotCI specifcally intended for examining Differential Item Functioning from ConQuest output.
Plots a Wright Map for a single person (similar to a kidmap). On the person side, highlights their estimated ability and a range of one standard error. On the item side, draws lines representing item difficulties at which they are expected to have a 20%, 40%, 50%, 60%, and 80% chance of success.
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.
This function accepts a matrix of delta parameters and converts them to thresholds (using a threshold of .5). It can also take as input a CQmodel object or a filename of a ConQuest show file.
The itemData and personData functions take CQmodel objects (or ConQuest output files) as inputs and return a vector or matrix. They were originally developed for use by wrightMap, but are separated out here to allow the outputs to be sent to other plotting functions.
providing 
.