generate_tirt_lavaan_syntax: Generate lavaan Syntax for Thurstonian Models

In autoFC: Automatic Toolkit for Construction, Optimization, Scoring and Simulation of Forced-Choice Tests

Generate lavaan Syntax for Thurstonian Models

Description

Generates the syntax required to fit either a Second-Order Thurstonian Factor Model or a First-Order Thurstonian IRT Model in lavaan.

Usage

generate_tirt_lavaan_syntax(
  n_blocks,
  block_size,
  key_matrix,
  trait_col,
  key_col,
  cor_matrix = NULL,
  model_type = c("TFM", "TIRT"),
  force_positive_variances = TRUE,
  more_constraints = ""
)

Arguments

n_blocks	Integer. Number of blocks in the questionnaire.
block_size	Integer. Number of items per block.
key_matrix	A data.frame indicating item trait and item sign.
trait_col	Character string. The name of the column in key_matrix indicating the trait measured by the item.
key_col	Character string. The name of the column in key_matrix indicating the keying direction of the item (e.g., positive/negative).
cor_matrix	Optional matrix. Starting values for trait correlations.
model_type	Character. Either "TFM" (Second-Order Thurstonian Factor Model) or "IRT" (First-Order).
force_positive_variances	Logical. If TRUE, prevents Heywood cases. In "Factor" models, utility variances > 0.0001. In "IRT" models, utility variances and derived correlated errors > 0.0001. Defaults to TRUE.
more_constraints	Additional lavaan syntax strings for constraining certain parameters if needed.

Value

A character string containing the lavaan model syntax.

autoFC documentation built on July 14, 2026, 5:07 p.m.