parse_mplus_polychoric: Parse Mplus Polychoric Correlation Matrix from Output File

In bifactory: (Bifactor) ESEM with Continuous (MLR) or Ordinal (WLSMV) Data

Parse Mplus Polychoric Correlation Matrix from Output File

Description

Reads a Mplus .out file and assembles the polychoric (tetrachoric) correlation matrix that Mplus prints under SAMPLE STATISTICS when SAMPSTAT is requested in the OUTPUT section.

Usage

parse_mplus_polychoric(out_file)

Arguments

out_file

Character. Full path to a Mplus .out file that contains a CORRELATION MATRIX (WITH VARIANCES ON THE DIAGONAL) section. This section is written when SAMPSTAT appears in the OUTPUT block of the Mplus input file.

Details

The matrix can be passed directly to besem_ordered via the r_obs_override argument so that R's DWLS optimisation uses the same polychoric estimates as Mplus, eliminating rotational discrepancies caused by differences in the polychoric estimators.

Value

A named, symmetric numeric matrix of polychoric correlations with 1s on the diagonal. Row and column names are the item names as reported by Mplus (typically upper-case).

Examples

## Not run: 
# Reads a polychoric matrix from a Mplus .out file (SAMPSTAT output),
# so it needs a .out produced by a licensed Mplus run.
R_mplus <- parse_mplus_polychoric(
  "path/to/besem_measurement.out"
)
dim(R_mplus)   # 18 x 18

# Use as input to besem_ordered so R rotates from the same matrix as Mplus
fit_b <- besem_ordered(
  data             = mydata,
  specific_factors = factor_items,
  r_obs_override   = R_mplus
)

## End(Not run)

bifactory documentation built on Oct. 28, 2026, 1:06 a.m.