link-class {plink}R Documentation

Class "link"

Description

The formal S4 class for link. This class compiles the linking constants, item parameter descriptive statistics, and iteration/objective/convergence information for the moment methods and characteristic curve methods of a separate calibration linking procedure.

Objects from the Class

Objects can be created by calls of the form new("link", ...), but this is not encouraged. Use the function link[=plink-methods{plink} instead.

Slots

constants:
list of linking methods where the list elements include the linking constants. For unidimensional models, each element is a vector of length two containing a slope and intercept to adjust the SD and mean respectively. For multidimensional models, each element is a list with a matrix (or set of matrices) to resolve rotational indeterminacy and scale, and a vector of translation constants to adjust the mean of each dimension.
descriptives:
data.frame or list containing the item parameter descriptive statistics
iterations:
vector of the number of optimization iterations for the Haebara and Stocking-Lord methods
objective:
vector of criterion values for HBcrit and SLcrit at the point of convergence for the Haebara and Stocking-Lord methods
convergence:
character vector identifying the type of convergence reached under the Haebara or Stocking-Lord optimizations. (see http://netlib.bell-labs.com/cm/cs/cstr/153.pdf for more information on the output values)
base.grp:
numeric value indicating the base group for the calibration
n:
vector identifying the total number of common items, the number of dichotomous common items, and the number of polytomous common items
grp.names:
character vector of group names
mod.lab:
character vector identifying the dichotomous and/or polytomous models used to model the item responses
dilation:
character value identifying the dilation approach used when estimating multidimensional linking constants
include.mcm.nrm:
logical vector indicating whether multiple-choice model or nominal response model items were included in the computation of the linking constants

Author(s)

Jonathan P. Weeks weeksjp@gmail.com

See Also

plink


[Package plink version 1.0.0 Index]