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 20-70 items, using multiple linear regression procedures are out of the question from a practical standpoint. Appreciate your comments!