We left off in our last episode with a teaser on why the blessed Perry Preschool Project, Carolina Abecedarian Project, and Chicago Child-Parent Centers Program don’t prove what many people like to pretend they prove; the long-term effectiveness, let alone cost-effectiveness, of current large-scale preschool programs.

Let’s begin with the fact that these programs were all small-scale, intensive, and targeted at the most disadvantaged children.

Now let’s look at some highlights of the other problems with using these as evidence in support of government preschool programs:

The Perry Preschool Project was an early-education intervention “experiment” initiated by researchers at the High/​Scope Educational Research Foundation in 1962 and concluded in 1965. Project researchers analyzed the effect of home visits and preschool on outcomes for an unusual sample of 58 low-income children with IQs between 70 and 85 compared to a “control” group of 65 other children who did not attend the preschool program or receive home visits.

Researchers concluded that the positive effects of the program on outcomes such as future earnings and crime rates far outweighed the costs, giving taxpayers a return of $7.16 for every dollar invested. However, there are a number of problems with the Perry Preschool Program and the associated analyses that render them unreliable and unsuitable for estimating the effects of the large-scale programs currently under consideration in state legislatures:

One analysis noted that “the Perry Project poses a number of methodological difficulties” that call into question any conclusions about the effects of the program, positive or negative. Assignment to the preschool treatment and “control” groups was not completely random — an absolute requirement for valid experiments. And the children in the preschool program had to have parents home during the day — a requirement “resulting in a significant difference between control and intervention groups on the variable of maternal employment” that also calls into question any results.

Other criticisms included:

• Twisting the Data: Program researchers expanded the standard definition of “statistical significance” in order to find positive effects. Most effects disappeared when the scientific standard was used.

• More than Preschool: The program included home visitations in addition to preschool, which made it difficult if not impossible to determine whether preschool alone had significant positive effects.

The Abecedarian Project was an intensive early-intervention program begun in 1972 that placed participating infants, who were on average at 4.4 months old, “in an eight-hour-a-day, five-day-per-week, year-round educational day care center” where they “received free medical care, dietary supplements, and social service support for their families.” Half of the children in this intensive infant intervention program received three more years of educational assistance, as did half of the children in the control group that did not participate in the intervention program as infants and toddlers.

Project researchers found that the infants who received the intensive early intervention scored higher than the control children on cognitive and academic tests at age 12 and 21. There are, however, a number of problems with the Abecedarian Project and the associated analyses that render them unreliable and unsuitable for estimating the effects of the large-scale programs currently under consideration in state legislatures:

• Much More than Preschool: The most obvious and serious problem with this “preschool” program is that the intervention was nothing like the preschool programs currently being considered or in effect. The Abecedarian Project was an intensive, long-term intervention beginning in infancy, and it can therefore shed little if any light on the effects of preschool on 3 or 4 year-olds.

• Methodological Problems: Studies reporting effects from the Abecedarian Project generally focus on the differences between the treatment and control groups at later ages. Herman H. Spitz, a well-respected academic psychologist specializing in measuring intelligence among those with developmental disability, notes that the advantage found later emerged when the children were just 6 months old. Spitzer rightly concludes, “We need to understand why an additional 4.5 years of intensive intervention had so little effect that, at six years of age (and older), the difference between the intervention and control groups was not appreciably different than it had been at six months of age.”

The Chicago Child Parent Center Program was an early-education and family intervention begun in 1985 involving 989 low-income children in Chicago. Researchers concluded that, compared to the 550 children who did not receive the intervention, children in the program had a “higher rate of high school completion; more years of completed education; and lower rates of juvenile arrest, violent arrests, and school dropout.” This study has been used in recent years by a RAND analysis that claims a universal preschool program would return $2.62 for every dollar invested.

Again, however, there are a number of problems with the Chicago Child Parent Center Program and the associated analyses that render them unreliable and unsuitable for estimating the effects of the large-scale programs currently under consideration in state legislatures:

• More than Preschool—Parenting: As the name of the program implies, the Chicago Child Parent Center Program involved extensive interventions with parents that involved “a multifaceted parent program that includes participating in activities in the parent resource room with other parents (e.g., educational workshops, reading groups, and craft projects), volunteering in the classroom, attending school events and field trips, and completing high school; outreach activities including resource mobilization, home visitation, and enrollment of children.”

• More than Preschool—Tutoring: The intervention continued through 3^rd grade for some students, and involved tutoring, speech therapy, and medical services that are not a part of current preschool proposals and significantly raise the costs and difficulties of expanding to a state-wide program.

• Wild Extrapolations: The RAND study does not consider these important concerns regarding the Chicago Child Parent Center Program. Instead they uncritically apply the findings from this intensive family intervention program to a state-wide, universal preschool-only program. The researchers also arbitrarily assign middle and upper-income children benefits from preschool that no study of the Chicago Child Parent Center Program suggests they receive.

The fourth and final post is coming soon, with a response to some other objections …