IBM® SPSS® Amos™ 28
Specifies the value of the constant, r, in Appendix A of the User's Guide.
Syntax
object.ChiCorrect (r)
The ChiCorrect method syntax has the following parts:
Part |
Description |
object |
An object of type AmosEngine. |
r |
The constant r in Appendix A of the User's Guide. |
Placement: [1].
Default
r is the number of groups.
Remarks
When the EmuLisrel6 method is used, the default value for r cannot be changed.
The choice of r affects only the discrepancy function and standard errors. It does not affect parameter estimates.
There are few guidelines for departing from Amos's default value for r. Browne (1982, p. 98), mentions favorably a formula due to Swain (1975):
where
,
using the notation in Appendix A of the User's Guide.
The Swain formula is intended for the case of a single group with unconstrained means and intercepts, where the model is invariant under a constant scaling factor. A one-group model in which means and intercepts are unconstrained was called "invariant under a constant scaling factor" by Browne (1982, p. 77) if, given any parameter vector, , and a positive number, c, there exists * such that 
.
When means and intercepts are highly constrained, some consideration should be given to using the ChiCorrect method to specify r = 0.
See Also
