Data collection can be the most time- and cost-intensive part of developmental research. This article describes some long-proposed but little-used research designs that have the potential to maximize data quality (reliability and validity) while minimizing research cost. In "planned missing data designs", missing data are used…

The present study reports two investigations; the first concerning the relationship between WISC verbal-performance IQ discrepancy and reading and spelling retardation, the second representing an analysis of the spelling errors made by these children. (Author)