The Michigan School Readiness Program found among those who attended preschool 24 percent more growth in vocabulary knowledge, 64 percent more growth in math and 22 percent more growth in print awareness. The Chicago Longitudinal Study -- CLS -- found preschool programs resulted in higher school achievement into adolescence. These students were 29 percent more likely to finish high school, 41 percent less likely to be placed in special education and 40 percent less likely to repeat a grade. The HighScope Perry Preschool project and a Head Start evaluation found similar results regarding high school completion.
Preschool attendance can decrease problem behavior. The CLS found that those who attended a preschool program were less likely to engage in delinquent behavior, had a 33 percent lower rate of juvenile arrest and a 42 percent lower arrest rate for violent crimes. The Perry preschool project also reported fewer crimes were later committed by their preschool participants, and of the Head Start preschool participants, only one-third as many -- 5 percent versus 15 percent -- were arrested for crimes.
Preschool programs, as opposed to day care centers, are more likely to promote child-initiated activities, and there is some indication that such activities contribute to the later development of a greater sense of personal and social responsibility. Children who attend preschool show benefits in adulthood including less smoking, substance abuse and depression. They also are more likely to hold a job and to have higher earnings.
There is a cost benefit to society when children attend preschool. For every dollar spent, an estimated $7.10 is returned to society through taxes on earnings, criminal justice savings and reductions in school remedial services. Over a lifetime this can be as much as $11, adding such things as welfare savings and medical savings as result of less smoking and substance abuse. However, the savings are not what they could be. According to the 2012 edition of "Education at a Glance," the United States ranks 28th of 39 countries in the percentage of 4-year-olds attending preschool, at 69 percent.