The mental growth patterns of 204 children were investigated on four different test occasions covering a five-year period, ages six to 11. There is no evidence of intellectual differentiation after age six nor is there a systematic decline in size of WISC subtest intercorrelations with increasing age. (Authors)

A sample of over 3,000 mildly retarded adolescents and young adults were administered a newly designed picture-inquiry instrument to measure vocational interest and knowledge. (Author)

An examination of the weaknesses of the common statistical approaches suggests that change scores are unnecessary and often even inappropriate for statistical studies. Alternative statistical procedures are suggested. (Author/VW)

In this comment a recent attempt by Samuel A. Livingston to develop a theory of reliability for criterion-referenced measures is critiqued. For Livingston's rejoinder see TM 500 560. (Authors/MB)