Jackknifing an Item Response Model
This function performs a Jackknife procedure for estimating
standard errors for an item response model. The replication
design must be defined by IRT.repDesign
.
Model fit is also assessed via Jackknife.
Statistical inference for derived parameters is performed
by IRT.derivedParameters
with a fitted object of
class IRT.jackknife
and a list with defining formulas.
IRT.jackknife(object,repDesign, ... ) IRT.derivedParameters(jkobject, derived.parameters ) ## S3 method for class 'gdina' IRT.jackknife(object, repDesign, ...) ## S3 method for class 'IRT.jackknife' coef(object, bias.corr=FALSE, ...) ## S3 method for class 'IRT.jackknife' vcov(object, ...)
object |
Objects for which S3 method |
repDesign |
Replication design generated by |
jkobject |
Object of class |
derived.parameters |
List with defined derived parameters (see Example 2, Model 2). |
bias.corr |
Optional logical indicating whether a bias correction should be employed. |
... |
Further arguments to be passed. |
List with following entries
jpartable |
Parameter table with Jackknife estimates |
parsM |
Matrix with replicated statistics |
vcov |
Variance covariance matrix of parameters |
## Not run: library(BIFIEsurvey) ############################################################################# # EXAMPLE 1: Multiple group DINA model with TIMSS data | Cluster sample ############################################################################# data(data.timss11.G4.AUT.part, package="CDM") dat <- data.timss11.G4.AUT.part$data q.matrix <- data.timss11.G4.AUT.part$q.matrix2 # extract items items <- paste(q.matrix$item) # generate replicate design rdes <- CDM::IRT.repDesign( data=dat, wgt="TOTWGT", jktype="JK_TIMSS", jkzone="JKCZONE", jkrep="JKCREP" ) #--- Model 1: fit multiple group GDINA model mod1 <- CDM::gdina( dat[,items], q.matrix=q.matrix[,-1], weights=dat$TOTWGT, group=dat$female +1 ) # jackknife Model 1 jmod1 <- CDM::IRT.jackknife( object=mod1, repDesign=rdes ) summary(jmod1) coef(jmod1) vcov(jmod1) ############################################################################# # EXAMPLE 2: DINA model | Simple random sampling ############################################################################# data(sim.dina, package="CDM") data(sim.qmatrix, package="CDM") dat <- sim.dina q.matrix <- sim.qmatrix # generate replicate design with 50 jackknife zones (50 random groups) rdes <- CDM::IRT.repDesign( data=dat, jktype="JK_RANDOM", ngr=50 ) #--- Model 1: DINA model mod1 <- CDM::gdina( dat, q.matrix=q.matrix, rule="DINA") summary(mod1) # jackknife DINA model jmod1 <- CDM::IRT.jackknife( object=mod1, repDesign=rdes ) summary(jmod1) #--- Model 2: DINO model mod2 <- CDM::gdina( dat, q.matrix=q.matrix, rule="DINO") summary(mod2) # jackknife DINA model jmod2 <- CDM::IRT.jackknife( object=mod2, repDesign=rdes ) summary(jmod2) IRT.compareModels( mod1, mod2 ) # statistical inference for derived parameters derived.parameters <- list( "skill1"=~ 0 + I(prob_skillV1_lev1_group1), "skilldiff12"=~ 0 + I( prob_skillV2_lev1_group1 - prob_skillV1_lev1_group1 ), "skilldiff13"=~ 0 + I( prob_skillV3_lev1_group1 - prob_skillV1_lev1_group1 ) ) jmod2a <- CDM::IRT.derivedParameters( jmod2, derived.parameters=derived.parameters ) summary(jmod2a) coef(jmod2a) ## End(Not run)
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