Ten scientific studies with different samples (listed in this table) have been conducted on the Abecedarian Approach (2A). Led by Craig Ramey, the first two Randomized Controlled Trials (RCTs) included children at risk from multiple social conditions such as poverty, young maternal age, or low parental education. The third RCT, headed by Ruth Gross, included almost 1,000 children across eight states. They entered the study as prematurely born, low birth weight infants and were from all social classes. These three studies demonstrated the early and lasting benefits of 2A delivered through high quality group child care supplemented by home visiting. Extended follow up on these first three RCTs revealed a wide variety of benefits for the children and families who received the 2A in the first three or five years of life. The following areas of long-term decrease or increase (over the control group) were reported in multiple peer-reviewed journal articles.
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Special Education placements
Symptoms of depression
Smoking and drug use
Hypertension, blood pressure
Cognitive skills (IQ)
Reading and math skills
Years in school, including college
University graduation rates
Full-time, qualified employment
Healthy life style
The educational program or intervention in all of the studies listed in the table referenced above was the full Abecedarian Approach (Language Priority, Enriched Caregiving, Conversational Reading, and LearningGames®) except for the Cerebral Palsy study which used only the LearningGames® element of the Approach. Two of the recent studies focused on Indigenous children and families in Canada and Australia. The study in Australia, which will be submitted for publication in 2019, was a cohort study rather than an RCT, since we choose to intervene with every child in two remote villages. Abecedarian 10 is a particularly interesting study since it was conducted in three middle- and low-income countries and showed that home visits every two weeks delivering 2A produced complete cognitive catch-up by age 36 months for children from low-resource families. A new RCT study (not yet in the table above) has received funding and is scheduled to begin in 2019 in Denmark. Frances Campbell was the Principal Investigator on most of the adult follow-ups of the original Abecedarian study.
Selected Articles in Peer-reviewed Journals
Hundreds of peer-reviewed articles and book chapters have been published on Abecedarian research since the early 1970s. Below are links to a few of them over the years. New analyses of long-term effects are still being conducted and new studies using the Abecedarian Approach in different contexts and with different samples are being initiated.
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Note: This article uses the generic term EDI (Early Developmental Intervention) for 2A. It also references Partners for Learning (now out of print) which was a revised publication of 2A.
Note: Partners for Learning (now out of print) was a revised publication of 2A
Sample Finding from an Abecedarian Study
In the low birth weight Abecedarian study (called IHDP), dividing the children by their mother’s educational level, produced a classic pattern in the control group (the yellow bars in the figure below) with a clear, stair-step relationship in the children’s age-three Stanford-Binet cognitive scores. This “social gradient,” is common in a variety of child health, employment, and educational outcomes.
Child’s Stanford-Binet IQ at age 36 months by mother’s education
But when we look at the randomly assigned group that got 2A for the first three years of life, the gradient is substantially flattened. The three red bars on the left are very nearly the same height. To achieve this equalization, a substantial improvement (over the control group) has to occur for the treated group of children who had mothers with the lowest education – the red bar that is farthest to the left of the figure. The only children who did as well without the program were children of mothers with four-year university degrees. So, there is good news: Children from families that need it most reap big benefits from participating in an early Abecedarian program during the first three years of life. And there is more good news: Children from most families benefit – although not quite as much as those in the households with mothers of the lowest education.
Ramey, C. T. & Ramey, S. L. (1998). Prevention of intellectual disabilities: Early interventions to improve cognitive development. Preventive Medicine, 27, 224–232.