mcIRT (version 0.41)

NLM.sim: Simulates data according to the Nested Logit Model

Description

This function simulates data according to the Nested Logit Model.

Usage

NLM.sim(Parlist, pp)

Arguments

Parlist

A list of numerical vectors with item parameters has to be committed. Note that the zeta parameters as well as the lambda parameters have to add up to 0 for each item. For details concerning the structure of the list see section 'Details'.

pp

A numerical vector of person parameters.

Value

The function returns a length(pp)*length(Parlist) data.frame.

Details

The structure of the Parlist is as follows:

• Vector for Item 1: c(slope, intercept, zeta1, zeta2, ..., lambda1, lambda2, ...)
• Vector for Item 2: c(slope, intercept, zeta1, zeta2, ..., lambda1, lambda2, ...)
• etc.

References

Suh, Y., & Bolt, D. M. (2010). Nested logit models for multiple-choice item response data. Psychometrika, 75, 454-473.

See Also

NRM.sim

nelm

Examples

# item parameters

Item1 <- c(1,-2,c(-0.5,0.3,0.2),c(-0.5,-0.3,0.8))
names(Item1) <- c("a","b",paste("zeta1",1:3,sep=""),paste("lamb",1:3,sep=""))

Item2 <- c(1,-1,c(-0.5,-0.3,0.8),c(-0.5,0.3,0.2))
names(Item2) <- c("a","b",paste("zeta1",1:3,sep=""),paste("lamb",1:3,sep=""))

Item3 <- c(1,0,c(-0.5,-0.3,0.8),c(-0.5,0.3,0.2))
names(Item3) <- c("a","b",paste("zeta1",1:3,sep=""),paste("lamb",1:3,sep=""))

Item4 <- c(1,1,c(-0.5,-0.3,0.8),c(-0.5,0.3,0.2))
names(Item4) <- c("a","b",paste("zeta1",1:3,sep=""),paste("lamb",1:3,sep=""))

Item5 <- c(1,2,c(-0.5,-0.3,0.8),c(-0.5,0.3,0.2))
names(Item5) <- c("a","b",paste("zeta1",1:3,sep=""),paste("lamb",1:3,sep=""))

ParList <- list(Item1=Item1,Item2=Item2,Item3=Item3,Item4=Item4,Item5=Item5)


# person parameters
pp <- rnorm(1000)

# simulate
sim.nlm.1 <- NLM.sim(ParList,pp)