To eliminate maturation as a factor in the pretest-posttest design, pretest scores can be converted to anticipate posttest scores using grade equivalent scores from standardized tests. This conversion, known as historical regression, assumes that without specific intervention, growth will continue at the rate (grade equivalents per year of…

Identifying the effects of the New York State Experimental Prekindergarten Program on the development of children requires that a broad array of data be analyzed. In studying the effects of the program, the evaluation unit is interested in determining whether there is an overall effect, and whether children of different ages and different levels…