Tools for Statistical Procedures


Gamma Hat 

This document and spreadsheet explain how to calculate the Gamma Hat fit index for use in Confirmatory Factor Analysis and Structural Equation Modeling.

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The Gamma Hat index
(185.3 kB, PDF)

The Akaike Information Criterion

The Akaike Information Criterion can be used to evaluate whether the best fitting model is better than the comparison model. The AIC Evaluation Procedure spreadsheet allows you to enter two AIC values and determine whether one model has better fit than the comparison model. Small differences in AIC will not be defensibly better than comparison models. This helps you determine if the difference is sufficiently large to prefer one model over another.

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AIC evaluation procedure
(11.7 kB, EXCEL)

Equating PAT and e-asTTle scores

We have been asked how to equate PAT and e-asTTle scores. To the best of our knowledge no formal equivalence study has been published. This note provides rationale for using stanines as basis of equating and provides stanine tables for e-asTTle reading and mathematics scores.