An alternative to ability grouping for instructional purposes exists. Cognitive developmental grouping (CDG), sometimes labeled "tracking" or "pacing," organizes students in terms of similar learning styles and takes into consideration the child's intellectual maturation rather than performance within a particular curriculum package. In order to successfully use CDG, teachers must understand and identify each child's developmental learning style in order to appropriately place the youngster for instruction. Children assigned to instruction by developmental level will, therefore, no longer be identified as members of high, middle, or low ability groups, but rather as preoperational, concrete operational, or formal operational learners. These developmental levels are characterized, respectively, by inability to consider another's position and the use of short-term memory; the ability to learn initially by concrete discovery and then apply earlier learning to new and sometimes novel situations; and by abstract learning. Abstract learning is rare among children and adults, including elementary school teachers. To assess children's level of development, teachers should first test for conservation and class inclusion. They should continuously reassess and readjust group membership, as children progress rapidly from one level to the next once appropriate schema have been developed. Guidelines are offered for designing developmentally appropriate instruction. (RH)