As Figure 3.2 shows, the normative group began kindergarten with substantially higher scores on the Number Knowledge Test than children in the treatment and the control groups. The gap indicated a developmental lag that exceeded one year, and for many children in the treatment group was closer to two years. By the end of the kindergarten year, however, the Number Worlds children narrowed the gap with the normative group to a small fraction of its initial size. By the end of the second grade, the treatment children actually outperformed the magnet school group. In contrast, the initial gap between the control group children and the normative group did not narrow over time. The control group children did make steady progress over the three years; however, they were never able to catch up.
FIGURE 3.2 Mean developmental scores on number knowledge test at four time periods.
administrators need to know what type of implementation of a specific curriculum produces what results, compared with the alternatives before them. Yet to provide the information that is most useful to practice is a major undertaking. These questions are answerable, but research carefully designed to provide those answers will take a substantial investment.