plot: S3 Methods: plot

In ForceChoice: Forced-Choice Modeling Based on Item Response Theory and Cognitive Diagnostic Models

S3 Methods: plot

Description

Draws log-likelihood trace plots for fitted ForceChoice model objects. Stan, iStEM, and EM fits are visualised through the same convergence target: the total log-likelihood recorded across iterations of the corresponding estimation algorithm.

Usage

## S3 method for class 'MIRT'
plot(x, y = NULL, ...)

## S3 method for class 'MGPCM'
plot(x, y = NULL, ...)

## S3 method for class 'MGGUM'
plot(x, y = NULL, ...)

## S3 method for class 'FCMIRT'
plot(x, y = NULL, ...)

## S3 method for class 'FCDCM'
plot(x, y = NULL, ...)

## S3 method for class 'FCGGUM'
plot(x, y = NULL, ...)

## S3 method for class 'FCGDINA'
plot(x, y = NULL, ...)

## S3 method for class 'TIRT'
plot(x, y = NULL, ...)

Arguments

x	A fitted model object of class "MIRT", "MGPCM", "MGGUM", "FCMIRT", "FCDCM", "FCGGUM", "FCGDINA", or "TIRT".
y	Ignored.
...	Ignored.

Details

The horizontal axis is the saved Stan iteration, iStEM iteration, or EM iteration. The vertical axis is the summed log-likelihood. Stan plots use log_lik or log_lik_group from generated quantities and draw all chains in one panel. iStEM plots use the iteration-level iStEM$logLik.trace, and the stable chain is the final M * B iStEM iterations. EM plots use EM$logLik.trace. For Stan and iStEM fits, a vertical dashed line marks the stable-chain boundary. EM fits do not have a stable-chain boundary.

Value

Invisibly returns NULL. Plots are produced as a side effect on the current graphics device.

Methods (by class)

• plot(MIRT): Log-likelihood trace plot for MIRT objects.

• plot(MGPCM): Log-likelihood trace plot for MGPCM objects.

• plot(MGGUM): Log-likelihood trace plot for MGGUM objects.

• plot(FCMIRT): Log-likelihood trace plot for FCMIRT objects.

• plot(FCDCM): Log-likelihood trace plot for FCDCM objects.

• plot(FCGGUM): Log-likelihood trace plot for FCGGUM objects.

• plot(FCGDINA): Log-likelihood trace plot for FCGDINA objects.

• plot(TIRT): Log-likelihood trace plot for TIRT objects.

ForceChoice documentation built on Sept. 13, 2026, 1:06 a.m.