The transition to elementary school spans several years in a child's life. For children to progress during this critical period, they must have learning opportunities that are appropriate to their changing developmental levels. Unfortunately, measurement technology that currently dominates assessment practice does not lend itself well to the task of promoting development. Assessment instruments designed to serve teaching and learning initiatives must meet three criteria: they must assess children's abilities, they must be capable of reflecting development during the long transition period, and they must provide information that can be used to plan developmentally appropriate learning opportunities. Norm-referenced and criterion-referenced achievement tests do not meet these criteria. However, the path-referenced approach provides developmental information by referencing a child's performance to a position on a path of development. The Measurement and Planning System, a measurement based on the path-referenced approach, emphasizes social competence, higher order thinking skills, and includes empirically validated developmental progressions that reflect a movement from simple to more complex forms of knowledge. In the 1987-1988 program year, the Ford Foundation allocated funding for a series of studies to examine the role of the Measurement and Planning System in facilitating the transition of Head Start children to the elementary school. The studies found that the Measurement and Planning System in kindergarten had a positive effect on ability during kindergarten. (Contains 23 references.) (MM)