This project examined some of the common constraints on reliable cognitive assessment for children over time. Repeated measures design (n = 133) was with younger (5 & 6 year old, n = 64) and older (7 & 8 year old, n = 69) children. Results showed that children's self-concepts moderated the test-retest reliability over extended intervals for younger and older children. Social self-categorizations moderated slightly the test-retest reliability for both age groups. For younger children only, personal self-categorization and self-reported talking about items moderated the reliability. In contrast, there were no moderators of test-retest reliability for shorter retest intervals. Other experiences, including recall, recognition and self-reported reflection on the content, did not moderate the test-retest reliability. (Contains 10 tables.)