Differential Item Functioning Using Robust Scaling

Documentation for package ‘robustDIF’ version 0.2.0

.onLoad	Registers S3 methods at load time: - print for class "rdif" - plot for class "rdif" - summary for class "rdif"
a_fun	The R-DIF scaling function for item slopes.
bsq_weight	The bi-square weight function.
delta_test	Wald test of differential test functioning.
dif_test	Wald tests of differential item functioning (DIF).
d_fun	The R-DIF scaling functions for item intercepts / thresholds.
format_pars	Helper function used to format parameters estimates
get_lavaan_pars	Extract item parameter estimates and their covariance matrix from 'lavaan'.
get_mirt_pars	Extract item parameter estimates and their covariance matrix from 'mirt'.
get_model_parms	Extract and format item parameter estimates and their covariance matrix
get_starts	Compute starting values for 'rdif'.
grad_a	The gradient matrix of 'a_fun'.
grad_d	The gradient matrix of 'd_fun'.
lts	The least trimmed squares (LTS) estimate of location
psi	The bi-square psi function.
psi_prime	The derivative of the bi-square psi function.
rdif	Estimate IRT scale parameters using the robust DIF procedure.
rdif.eg	Example data set for R-DIF functions.
rho	The bi-square rho function.
rho_grid	Compute a grid of bi-square Rho values
vcov_y	The covariance matrix of IRT scaling functions.
y_fun	R-DIF scaling functions for item intercepts/thresholds and slopes.