TABLE 4-1 Longitudinal Studies of Child Development Programs

Researcher

Age Group

Ratio

Group size

Duration

Abecedarian Project (Campbell and Ramey, 1994)

Infants, preschool

1:3

1:6

14

12

5 years

Brookline Early Education Project (Hauser-Cram et al.,1991)

Infants, preschool

1:1

16

18

5 years

Early Childhood Education Project (Sigel et al., 1973; Cataldo, 1978)

2-3 years

1:7

22

3 years

Early Training Project (Gray et al., 1982)

Preschool

1:5

20

2 or 3 years

Family Development Research Program (Honig and Lally, 1982)

1-2 years

Infants, preschool

1:4

8

5 years

Harlem Training Project (Palmer, 1983)

Preschool

1:1

NA

1-2 years

Infant Health and Development

1-2 years

1:3

6 8

3 years

Program (Ramey et al., 1992; Infant Health and Development Program Consortium, 1990)

2-3 years

1:4

 

 

Milwaukee Project (Garber, 1988)

2 years

3 years preschool

1:2

1:3

1:7

?

6 years

Perry Preschool Project (Schweinhart and Weikart, 1993)

Preschool

1:5

20-25

2 years

Project CARE (Wasik et al., 1990)

Infants, preschool

1:3

1:6

14

12

5 years

 

SOURCES: Data from Frede (1998); Lazar et al. (1977); and NRC (2001b:134-135).

The principle that intensity matters applies to two-generation programs that work with parents as well. One home visit program (Powell and Grantham-McGregor, 1989) produced significant cognitive benefits with three visits per week but not with less frequent visits. Similarly, the Brookline Early Education Project (Hauser-Cram et al., 1991) reported significant cognitive and social benefits only from its most intensive two-generation interventions.



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