Skip to contents

Principal components of the residual correlations

Source: R/dimensionality.R
residual_pca.Rd

The first residual component (PC1) carries any second dimension; items with opposing loadings define the split used by the unidimensionality t-test. Loadings for the leading components and the eigenvalue table support inspection beyond the first component.

Usage

residual_pca(fit, n_components = 10)

Arguments

fit

A fitted object from rasch.

n_components

Number of leading components to return loadings and eigenvalue rows for (capped at the number of items).

Value

A list with the residual eigenvalues, their proportions, the first-component loadings (sorted), the loadings_matrix for the leading components, the eigen_table (component, eigenvalue, proportion, cumulative), and the first_eigenvalue.

Examples

set.seed(1)
d <- seq(-2, 2, length.out = 8)
X <- matrix(rbinom(500 * 8, 1, plogis(outer(rnorm(500), d, "-"))), 500, 8)
colnames(X) <- paste0("I", 1:8)
residual_pca(rasch(X))$first_eigen
#> [1] 1.295188