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Assessing Fit of Models With Discrete Proficiency Variables in Educational Assessment MCMC PPMC

Sinharay, Sandip; Almond, Russell G.; Yan, Duanli
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Bayesian Methods, Bayesian Residual, Item Fit, Markov Chain Monte Carlo (MCMC), Model Fit, Person-Fit, Posterior Predictive Model Checking (PPMC) Method


This work is a continuation of the recent work by Yan, Mislevy, and Almond (2003) on this data set. Two diagnostic tools that prove useful are Bayesian residual plots and an analog of the item characteristic curve (ICC) plots. A two-type statistic based on the latter plot shows some promise, but more work is required to establish the null distribution of the statistic. On the basis of the identified problems with the model used by Mislevy (1995), the suggested diagnostics are helpful to hypothesize an improved model that seems to fit better.

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