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The Research on Pre-K

A large and growing body of research shows that investing in high-quality pre-kindergarten education yields benefits for children, schools, and communities. This summary describes the short- and long-term benefits of high-quality pre-k programs and the potential cost savings to communities. In addition, it outlines the key program criteria that contribute to pre-k success.

Short-term benefits

There is strong evidence showing that young children who participate in high-quality pre-k programs enter school more ready to learn than their peers. The national Early Childhood Longitudinal Study—Kindergarten Cohort shows that students who attended a pre-k program scored higher on reading and math tests than children receiving parental care.1 Students who attended a child care center or other preschool program also showed gains, although former pre-k students exhibited the greatest achievement.

Several state studies have also documented significant cognitive gains for children who receive pre-k. In Georgia, children who attended the state’s universal program overcame the achievement gap they faced prior to enrolling in pre-k by the time they finished kindergarten.2 Children who received pre-k equaled or exceeded national norms in eight of nine standardized assessments by the end of their kindergarten year. A significant gap remained, however, between white and black children, which researchers attributed in part to factors related to family income differences.

Oklahoma, another state with pre-k for all children, has documented significant academic gains across all income and racial groups. Participation in pre-k was a more powerful predictor of children’s pre-reading and pre-writing scores than demographic variables such as race, family income, and mother’s education level.3 An evaluation of the program in Tulsa, the state’s largest school district, showed significant increases in letter-word identification, spelling, and applied problems among students on free or reduced-priced lunch and those not participating in the subsidy program.

Children of all racial groups also exhibited academic gains. In particular, the study found a narrowing of the achievement gap for Hispanic children. These students exhibited an eleven-month gain in letter/word recognition and six-month gain in applied problem solving compared to the corresponding gains (nine-months and three-months respectively) for white children.4

Effects of Tulsa Pre-K by Free Lunch Status, Race/Ethnicity, in Months5

One of the most far-reaching recent studies found marked increases in children’s skills across five states: Michigan, New Jersey, Oklahoma, South Carolina, and West Virginia. Overall, children in state pre-k posted vocabulary scores that were 31 percent higher and math gains that were 44 percent higher than those of non-participants.6 These gains placed pre-k children three to four months ahead of non-participants, largely due to participation in the state program. The greatest gains occurred in print awareness, where participants had an 85 percent increase, which suggests these outcomes strongly predict later reading success.

Long-term effects

Most long-term pre-k research has focused on whether program effects fade out over time or produce lasting benefits for participants. Three major longitudinal studies which began in the 1960s and 1970s—the High/Scope Perry Preschool Project, the Chicago Parent Centers, and the Abecedarian Project—show demonstrably positive effects of quality pre-k on the future lives of young children. These projects remain relevant since they tracked the short- and long-term progress of participants, including one study that followed former program participants and a control group through age forty.

In the High/Scope study, low-income black children randomly selected to receive the comprehensive preschool program showed impressive long-term results regarding educational progress, delinquency, and earnings. Seventy-seven percent of these youngsters eventually graduated from high school, compared with 60 percent from the control group. In adulthood pre-k participants were also less likely to be arrested for violent crimes, more likely to be employed, and more likely to earn higher wages than those in the comparison group.7

Among states with long-term results is Michigan, where children from the state pre-k program had higher pass rates on the fourth-grade literacy and math tests compared with non-participants.8

Cost Savings

High-quality pre-k programs also provide substantial cost savings to federal, state, and local governments. Numerous studies have shown a reduced use of special education services and lower grade retention among pre-k participants. In the Abecedarian study, for example, 24 percent of pre-k children received special education services, versus 48 percent of the control group. Given the high cost of these interventions pre-k can produce significant financial benefits for school districts.

Economic analyses have sought to quantify these and other societal outcomes (i.e., less delinquency, decreased dependence on public assistance, increased employment and earnings) in real dollars. Table 1 shows the cost benefits per $1 invested for each of three long-term pre-k studies.

Estimates for the long-term payback of a non-targeted voluntary, universal preschool program range from $2- to-$4 for every dollar spent.

Characteristics of Quality

As interest in pre-k has increased and more states have implemented pre-k programs, policymakers have identified core requirements for program success. These include: Highly trained teachers with expertise in early childhood education, learning goals tied to K–12 standards, low child/staff ratios, and small class sizes.

Teacher training

Model pre-k programs such as the Perry Preschool and Chicago Parent Centers validate the benefits of hiring teachers with a strong background in education and training. More recent state pre-k studies also document the effectiveness of programs with BA-certified teachers.9 Experts emphasize the need for teachers with college degrees who can deliver educational programming and who are paid at sufficient levels that promote retention. Among thirty-eight states with pre-k programs in 2007:

  • Twenty-two require a teacher to have at least a bachelor’s degree.
  • Thirty-two require teachers to have specialized training in pre-k or preschool.
  • Twenty-nine require pre-k teachers to obtain at least 15 hours of in-service training.10

In most cases, state pre-k programs have stronger teacher qualifications than those in the federal Head Start program. Only recently did Head Start require 50 percent of its teachers nationwide to possess at least a bachelor’s degree by October 2013.

Learning standards and alignment

There is wide agreement in the field that it is important for programs to have a set of learning guidelines in place to articulate what pre-k children should know and be able to do. As a result, most states have adopted some type of early learning or content standards. Georgia’s universal pre-k program, for example, has content standards in seven areas: Language and literacy, mathematics, science, social studies, arts, health and physical development, and social/emotional competence. Illinois also includes foreign language as a particular content area. The specific details of these standards, however, often differ between states.

Another way to promote learning goals is for states to align curriculum to provide a consistent framework of services for children aged three to eight or PK–3. Alignment of standards may be a necessary first step to sustain the positive effects of pre-k during elementary school, since children who attend low-quality schools often have the highest degree of preschool fadeout.11 Few studies, however, have examined the strength of this alignment and its impact on the quality of education.

Licensing and program standards

After years of researching high-quality programs, pre-k experts have identified several common structural characteristics of quality programs. These include a child/staff ratio of no more than 10:1, and a maximum class size of twenty or less. In model programs such as the High/Scope Project and the Abecedarian study, a single teacher was responsible, on average, for less than seven children. These studies also had small class sizes, from twelve in Abecedarian to seventeen in the Child-Parent Centers program.12


The evidence is strong that high-quality pre-k can have significant short- and long-term impacts on children and their communities. This summary highlights some of the most recent and compelling research in the field. More in-depth information on the subject can be found on the Center for Public Education’s web site at www.centerforpubliceducation.org.


  1. Gormley, W., Gayer, T., Phillips, D., and Dawson, B., 2004b. The Effects of Universal Pre-K on Cognitive Development. Washington, DC: Georgetown University, Center for Research on Children in the U.S.
  2. Henry, G., Ponder, B., Rickman, D., Mashburn, A., Henderson, L., and Gordon, C., 2004. An Evaluation of the Implementation of Georgia’s Pre-K Program: Report of the Findings from the Georgia Early Childhood Study. Atlanta: Georgia State University, Applied Research Center.
  3. William Gormley, Jr., Deborah Phillips, and Ted Gayer, &lquot;Preschool Programs Can Boost School Readiness,&rquot; Science 320 (June 27, 2008), pp.1723-24.
  4. Ibid.
  5. Professor William Gormley, Georgetown Public Policy Institute, Presentation to National School Boards Association, September 8, 2008.
  6. W. Steven Barnett, Cynthia Lamy, and Kwanghee Jung, &lquot;The Effects of State Prekindergarten Program on Young Children’s School Readiness in Five States&rquot; (Rutgers University, National Institute for Early Education Research, 2005).
  7. L. J. Schweinhart et al., Lifetime Effects: The High/Scope Perry Preschool Study Through Age 40 (2005).
  8. Gilliam, W. and Zigler, E., 2004. State Efforts to Evaluate the Effects of Pre-kindergarten 1977-2003. New Haven, Conn.: Yale University Child Study Center.
  9. Gormley et al. 2004a; Barnett, Lamy, and Jung 2005.
  10. Preschool Yearbook, 2007.
  11. (Bogard and Takanishi 2005)
  12. (Ackerman and Barnett 2006).

We gratefully acknowledge The Pew Charitable Trusts for its support of our work related to pre-kindergarten. The views expressed are those of the Center for Public Education and not necessarily those of The Pew Charitable Trusts.

Prepared by Chrisanne Gayl

For The Center for Public Education, 2008


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