IBM® SPSS® Amos™ 28
Controls whether Amos tries to fit a model that appears to be unidentified.
Syntax
object.AllowUnidentified ()
object.AllowUnidentified (tf)
The AllowUnidentified method syntax has the following parts:
Part |
Description |
object |
An object of type AmosEngine. |
tf |
(Boolean) Optional. If tf is True (the default), Amos tries to fit a model even if it appears to be unidentified. |
Placement: [1].
Default
When a model appears to be unidentified, Amos displays an error message, and quits.
Remarks
Attempting to fit an unidentified model is generally a bad idea for the following reasons: It uses more memory, and usually takes more time. It prevents Amos from using one of its most important tests for a correct solution, namely, that the matrix of second derivatives be positive definite. For hypothesis testing purposes, it requires Amos to make a correction to degrees of freedom based on the number of additional parameter constraints needed to achieve identifiability. The difficulty of numerically recognizing and diagnosing nonidentifiability is discussed in Appendix D.
See Also
