R: Test Equating Using the Kernel Method

kequate {kequate}

R Documentation

Test Equating Using the Kernel Method

Description

A function to conduct an equating between two parallel tests using kernel equating. Designs available are equivalent groups (EG), single group (SG), counterbalanced (CB), non-equivalent groups with anchor test using either chain equating (NEAT CE) or post-stratification equating (NEAT PSE) and non-equivalent groups using covariates (NEC).

Usage

kequate(design, ...)

Arguments

`design`	A character vector indicating which design to use. Possible designs are: EG, SG, CB, NEAT_CE, NEAT_PSE or NEC.
`...`	Further arguments which partly depend on the design chosen. (See section Details for further information.)

Details

Besides the above argument, additional arguments must be provided for the different equating designs.

EG design

‘x’ A vector of possible score values on the test X to be equated, ordered from the lowest to the highest score.

‘y’ A vector of possible score values on the test Y to be equated, ordered from the lowest to the highest score.

‘r’,‘s’ Numeric vectors containing the estimated or observed score probabilities for tests X and Y respectively. Alternatively objects of class ‘glm’.

‘DMP’, ‘DMQ’ The design matrices from the log-linear models for the estimated score probabilities for X and Y. Not needed if arguments r and s are of class ‘glm’.

‘N’, ‘M’ The sample sizes of the groups taking tests X and Y, respectively. Not needed if arguments r and s are of class ‘glm’.

‘hx’, ‘hy’ Optional arguments to specify the continuization parameters manually. (If linear=TRUE, then these arguments have no effect.)

‘hxlin’, ‘hylin’ Optional arguments to specify the continuization parameters manually in the linear case.

‘KPEN’ The constant used in deciding the optimal continuization parameter. Default is 0.

‘wpen’ An argument denoting at which point the derivatives in the second part of the penalty function should be evaluated. Default is 1/4.

‘linear’ Logical denoting if only a linear equating is to be performed. Default is FALSE.

‘irtx’, ‘irty’ Optional arguments to provide matrices of probabilities to answer correctly to the questions on the parallel tests X and Y, as estimated in an Item Response Theory (IRT) model.

‘smoothed’ A logical argument denoting if the data provided are pre-smoothed or not. Default is TRUE.

‘kernel’ A character vector indicating which kernel to use, either "gaussian", "logistic", "stdgaussian" or "uniform". Default is "gaussian".

‘slog’ The parameter used in defining the logistic kernel. Default is 1.

‘bunif’ The parameter used in defining the uniform kernel. Default is 0.5.

‘altopt’ Logical which sets the bandwidth parameter equal to a variant of Silverman's rule of thumb. Default is FALSE.

‘DS’ Logical which enables bandwidth selection with the double smoothing method.

SG design

‘x’ A vector of possible score values on the test X to be equated, ordered from the lowest to the highest score.

‘y’ A vector of possible score values on the test Y to be equated, ordered from the lowest to the highest score.

‘P’ The estimated or observed probability matrix for scores on tests X and Y, where the columns denote scores on test Y and the rows denote scores on test X. Alternatively a vector of score probabilities or an object of class ‘glm’, where the entries are ordered first by the Y-scores and then by the X-scores.

‘DM’ The design matrix used in the log-linear model. Not needed if the argument P is of class ‘glm’.

‘N’ The sample size. Not needed if the argument P is of class ‘glm’.

‘hx’, ‘hy’ Optional arguments to specify the continuization parameter manually. (If linear=TRUE, then these arguments have no effect.)