IBM® SPSS® Amos™ 28

If Null 1 is checked, the Null 1 model will be fitted and used to calculate CFI1 for each model generated by the specification search.

With incomplete data, both Saturated and Null 1 must be checked in order to fit the Null 1 model and to calculate CFI1.

In the Null 1 model, the observed variables are required to be uncorrelated. Their means and variances are unconstrained. This is the baseline "Independence" model in an ordinary Amos analysis when you do not perform a specification search. (See Appendix F for more about null models.)