The formal S4 class for irt.pars. This class contains the item parameters and characteristics of the item parameters for one or more groups. When parameters are included for two or more groups, the common items between the different groups are also included.
Objects of class
irt.pars contain all the information necessary to produce
expected response probabilities, linking constants (when data for two or more groups are
included), and to plot item response curves/surfaces, vector plots, and parameter
Objects can be created by calls of the form
new("irt.pars", ...), but this is
not encouraged. Use the function
matrix of item parameters for a single group or a list of matrices containing item parameters for two or more groups
vector with length equal to the number of items, identifying the number of response categories for each item for a single group or a list of response category vectors for two or more groups
poly.mod object for one group or a list of
poly.mod objects identifying the items associated with each IRT model (see class
poly.mod for more information)
a j x 2 matrix for j common items or a list of matrices identifying the common items between pairs of item parameters
logical vector identifying whether a given set of item parameters (i.e., for a given group) includes a location parameter
the number of groups (i.e. sets of item parameters)
numeric vector identifying the number of modeled dimensions
list.poly, by class
poly.mod, distance 2.
Jonathan P. Weeks email@example.com
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