Measuring children's self-concept with a Dutch version of the "self-perception profile for children": factorial validity and invariance across a nonclinic and a clinic group.

Harter's (1985) Self-perception Profile for Children (SPPC) is used to investigate whether the pattern and size of relations among the subscales in a clinic group are equivalent to those in a nonclinic group of children, and whether the items are perceived in the same way and with the same degree of accuracy across both groups. The first aspect indicates equivalence of structure, the latter equivalent measurement. Both are aspects of between-group invariance. It is essential to show evidence of these aspects before content-based comparisons are made between these groups. Using restrictive factor analysis, support was found for equivalence of structure. Equivalence of measurement was partially found. The items were perceived in the same way, but not with the same degree of accuracy. The conclusion is that the SPPC has sufficient between-group invariance to be used in studies with children in a clinic group.