8.10 Item-level Relative Fit measures (Cont’d)

The Wald statistic is defined by \[ W=[\mathbf{R}\mathbf{P}]^T[\mathbf{R}V(\mathbf{P})\mathbf{R}^T]^{-1}[\mathbf{R}\mathbf{P}] \] Recall that

\(H_0\): the simpler model can fit the item as well as the G-DINA model

\(H_1\): the simpler model cannot fit the item as well as the G-DINA model

What if two or more simpler models are retained?