sim_rrum_items function

Generate data from the rRUM

Randomly generate response data according to the reduced Reparameterized Unified Model (rRUM).

sim_rrum_items(Q, rstar, pistar, alpha)

Arguments

• Q: A matrix with $J$ rows and $K$ columns indicating which attributes are required to answer each of the items, where $J$ represents the number of items and $K$ the number of attributes. An entry of 1 indicates attribute $k$ is required to answer item $j$. An entry of one indicates attribute $k$ is not required.

• rstar: A matrix a matrix with $J$ rows and $K$ columns indicating the penalties for failing to have each of the required attributes, where $J$ represents the number of items and $K$ the number of attributes. rstar and Q

  must share the same 0 entries.

• pistar: A vector of length $J$ indicating the probabiliies of answering each item correctly for individuals who do not lack any required attribute, where $J$ represents the number of items.

• alpha: A matrix with $N$ rows and $K$ columns indicating the subjects attribute acquisition, where $K$ represents the number of attributes. An entry of 1 indicates individual $i$ has attained attribute $k$. An entry of 0 indicates the attribute has not been attained.

Returns

Y A matrix with $N$ rows and $J$ columns indicating the indviduals' responses to each of the items, where $J$

represents the number of items.

Examples

# Set seed for reproducibility
set.seed(217)

# Define Simulation Parameters
N = 1000 # number of individuals
J = 6 # number of items
K = 2 # number of attributes

# Matrix where rows represent attribute classes
As = attribute_classes(K) 

# Latent Class probabilities
pis = c(.1, .2, .3, .4) 

# Q Matrix
Q = rbind(c(1, 0),
          c(0, 1),
          c(1, 0),
          c(0, 1),
          c(1, 1),
          c(1, 1)
    )
    
# The probabiliies of answering each item correctly for individuals 
# who do not lack any required attribute
pistar = rep(.9, J)

# Penalties for failing to have each of the required attributes
rstar  = .5 * Q

# Randomized alpha profiles
alpha  = As[sample(1:(K ^ 2), N, replace = TRUE, pis),]

# Simulate data
rrum_items = sim_rrum_items(Q, rstar, pistar, alpha)

References

Culpepper, S. A. & Hudson, A. (In Press). An improved strategy for Bayesian estimation of the reduced reparameterized unified model. Applied Psychological Measurement.

Hudson, A., Culpepper, S. A., & Douglas, J. (2016, July). Bayesian estimation of the generalized NIDA model with Gibbs sampling. Paper presented at the annual International Meeting of the Psychometric Society, Asheville, North Carolina.

Author(s)

Steven Andrew Culpepper, Aaron Hudson, and James Joseph Balamuta