Date:  Thu, 14 May 1998 13:58:47 0400 
ReplyTo:  "John A. Schinka, Ph.D." <jschinka@COM1.MED.USF.EDU> 
Sender:  "SPSSX(r) Discussion" <SPSSXL@UGA.CC.UGA.EDU> 
From:  "John A. Schinka, Ph.D." <jschinka@COM1.MED.USF.EDU> 
Organization:  USF Health Sciences Center 
Subject:  SMCs 
ContentType:  text/plain; charset=usascii 
I am examining the characteristics of a personality scale
consisting of 33 items. The Reliability routine does not produce item
SMCs (squared multiple correlations) because the determinant of the
covariance matrix is essentially zero (this information provided via a
warning). Yet, the Factor routine, employing principal axis factoring +
promax, produces values for the communalities for each item. I believe
these communalities are the item SMCs. The calculated determinant for
this analysis is essentially zero. Can someone explain the
inconsistency here? Am I correct in assuming that the communalities are
the item SMCs? It seems unlikely, because the values are all <.70 and
I'm assuming the determinant problem is caused by multicollinearity.
Clarification?
Is there an easy way to determine the SMC for each item in a
matrix? As I'm examining about 100 scales of length from 2070 items,
using multiple linear regression procedures are out of the question from
a practical standpoint. Appreciate your comments!
