# DCM

## Introduction to Latent Attribute Network Analysis

A brief introduction of using Network Model to visualize latent attributes' hierarchy of Diagnostic Modeling.

## Latent Network Diagnostic Classfication Model

A Proposed Model Embeding Networking Modeling with DCM

## Introduce Descrepancy Measures

Descrepancy Measures This Blog is the notes for my recent project about reliability and model checking. Next I want to organize a little about one important concept in model checking - discrepancy measures. Descrepancy Measures $\chi^2$ measures for item-pairs (Chen & Thissen, 1997) $X^2_{jj'}=\sum_{k=0}^{1} \sum_{k'=0}^{1} \frac{(n_{kk'}-E(n_{kk'}))^2}{E(n_{kk'})}$ $G^2$ for item pairs $G^2_{jj'}=-2\sum_{k=0}^{1} \sum_{k'=0}^{1} \ln \frac{E(n_{kk'})}{n_{kk'}}$ model-based covariance (MBC; Reckase, 1997) $COV_{jj'} = \frac{\sum_{i=1}^{N}(X_{ij}-\overline{X_j})(X_{ij'}-\overline{X_{j'}}) }{N} \\ MBC_{jj'} = \frac{\sum_{i=1}^{N}(X_{ij}-E(X_{ij}))(X_{ij'}-E(X_{ij'}))}{N}$

## Posterior Predictive Model Checking for DCM

Model checking in Diagnostic Classification Models (DCM) is an underdeveloped area