IBM® SPSS® Amos™ 28

If Null 3 is checked, the Null 3 model will be fitted and used to calculate CFI3 for each model generated by the specification search.

With incomplete data, both Saturated and Null 3 must be checked in order to fit the Null 3 model and to calculate CFI3.

In the Null 3 model, the observed variables are required to be uncorrelated and to have zero means. Their variances are unconstrained. This is the baseline "Independence" model used by Amos 4.0.1 and earlier for models where means and intercepts are explicit model parameters. (See Appendix F for more about null models.)

There is little reason to fit the Null 3 model in the common situation where means and intercepts are not constrained, but are estimated for the sole purpose of allowing maximum likelihood estimation with missing data.

The Null 3 option is enabled only for models in which means and intercepts are explicit model parameters.