equat1pl: 1pl equating with optional elimination of linking DIF items

In eatModel: Educational Assessment Tools for IRT Modeling using Conquest or TAM

Description

Function does the 1pl linking according to equating.rasch from the sirt package. Moreover, optional elimination of items with linking DIF is allowed and linking error may be estimated via the jackknife method if testlets are specified.

Usage

equat1pl(results , prmNorm , item = NULL, domain = NULL, testlet = NULL, value = NULL, 
         excludeLinkingDif = TRUE, difBound = 1, iterativ = FALSE, 
         method = c("Mean.Mean", "Haebara", "Stocking.Lord"), itemF = NULL, 
         domainF = NULL, valueF = NULL)

Arguments

results	The object returned by getResults. Alternatively, a data.frame with item parameters of the focus group. In this case, additional arguments (itemF, domainF, and valueF) have to be defined.
prmNorm	Data frame with normed anchor item parameters. Data frame must have at least two columns: items and item difficulties. Use the further arguments 'item', 'domain', 'testlet' and 'value' to define the column in which the corresponding parameter can be found. If 'item', 'domain', 'testlet' and 'value' is NULL, prmNorm must have only two columns: First column items, second column item difficulties. Column names than are arbitrary.
item	Optional: Give the number or name of the item identifier column in prmNorm.
domain	Optional: Give the number or name of the domain name in prmNorm. Only necessary if item identifiers are not unique in prmNorm (for example, if one item occurs several times, with a global item parameter and a domain-specific item parameter. Domain names in prmNorm must match dimension names in the 'results' object.
testlet	Optional: Give the number or name of the testlet name in prmNorm. Only necessary if linking errors should be estimated via the jackknife method.
value	Optional: Give the number or name of the parameter column in prmNorm.
excludeLinkingDif	Logical. Should items with linking DIF excluded?
difBound	Defines the boundary. Items with absolut linking DIF greater than the boundary will be removed from the linking procedure.
iterativ	Logical. Should the exclusion of linking DIF items executed in an iterative loop?
method	Linking method
itemF	Optional: Give the number or name of the item column in results.
domainF	Optional: Give the number or name of the domain column in results.
valueF	Optional: Give the number or name of the parameter column in results.

Value

A list with equating information intended for further transformation by the transformToBista function.

Author(s)

Sebastian Weirich

Examples

# see example 5, 6, and 6a in the help file of defineModel()

eatModel documentation built on May 2, 2019, 6:49 p.m.