Microsoft Word Heckman final 2007-03-22c jsb doc

 

50

 

43

Figures A9a-d repeat this analysis for different race and income groups. 

44

Figures A10a-d repeat this analysis for different race and income groups. 

45

The recent California initiative to reduce pupil-teacher ratios ended in widely 

acknowledged failure (Stecher and Bohrnstedt). 

46

See Figure A11 for a diagram of the investment profile. 

47

Table A6, from Currie, describes some of the main programs, evaluated by 

randomized assignment, and their consequences. Table A7 shows the effects of large-

scale public early childhood programs which were not evaluated by randomized 

assignment. 

48

See Table A8. 

49

Arguably the experimental studies understate the value of early childhood 

interventions against “no intervention” because some of the control group children 

received treatment. See Heckman, LaLonde, and Smith for an additional discussion of 

randomization. 

50

Poverty status was determined by a formula that considered rooms per person in 

the child’s household, parental schooling and occupational level. The IQ range was 

labeled as “borderline educable mentally retarded” by the state of Michigan at the time of 

the experiment. Only children without an organic mental handicap were included in the 

study. 

 

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Some aspect of the assignment was clearly nonrandom. First, younger children 

were assigned to the same group as their older siblings. Two treatment children were 

transferred to the control group because their mothers were not able to participate in any 

classes or home visits because they were employed far from home. Four treatment 

children left the program before completing the second year of preschool when their 

families relocated and one control child died. Thus, the final sample consisted of 123 

children came from 100 families. In the control group, 41 families contributed 1 child 

each, and 12 families contributed 2 children each. In the treatment group, 39 families 

contributed 1 child apiece, 6 families contributed 2 children apiece, 1 family contributed 3 

and another 4 children. Assigning younger siblings to the same group effectively made 

the family, rather than the individual, the unit of analysis. Still, it is difficult to argue that 

assigning siblings at random would have been a better strategy. So-called spillovers to the 

control siblings from home visits would have been one possible source of bias since 

mothers cannot be expected to treat siblings in accordance with their experimental status. 

Another potential source of bias is spillover from one sibling to another. In any case, 

differences in background characteristics between the two experimental groups are 

virtually nonexistent, with the exception of much higher rates of maternal employment at 

program entry in the treatment group. 

 

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This number is low relative to other early education experiments. For instance, 

the student-teacher ratio for the Chicago Child-Parent Center and Expansion Program 

ranged from 8 to 12 (see Fuerst and Fuerst). 

53

Schweinhart, Barnes, and Weikart argue that the certification of the teachers is 

an important component in the success of the Perry preschool. 

54

The factors that were considered consisted of weighted measures of maternal 

and paternal education levels, family income, absence of the father from the home, poor 

social or family support for the mother, indication that older siblings have academic 

problems, the use of welfare, unskilled employment, low parent IQ, family members who 

sought counseling or support from various community agencies. Parental income and 

education were considered most important in calculating the index. 

55

 These costs depend on the stage of the program and are presented in detail in the 

next section. 

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See Schweinhart, et al. for a summary of results up through age 40. 

57

The difference in employment rates was only significant at age 19. 

58

Heckman notes that the Perry program tends to show stronger effects for girls 

than boys.  

59

 There is a cost benefit study of the Abecedarian program (Barnett and Masse), 

but it is highly speculative, so that we did not include it here. 

 

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Heckman, et al. present a comprehensive reanalysis of the Perry program. 

Similar reanalyses are being conducted for each major intervention. 

61

This task is being undertaken by a consortium housed at the Harris School, 

University of Chicago. 

62

See the evidence in Heckman, Stixrud, and Urzua. 

63

See Cunha et al. for a summary of this evidence and Knudsen, et al. 

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See the evidence in Cunha and Heckman (2006). 

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Table 1. Characteristics of the labor force aged 25 and over and components of 

change 1980, 2000, 2020 

(Millions of workers) 

Age Labor 

Force in 

1980 

Growth 

1980 – 

2000 

Labor 

Force in 

2000 

Growth 

2000 – 

2020 

Labor 

Force in 

2020 

25 – 54 

65.0 

35.1 

100.1 

3.0 

103.1 

55 - 64 

11.8 

2.2 

14.0 

12.5 

26.5 

65 

+ 

3.0 1.4 4.4 4.0 8.4 

Total 

79.8  38.7 118.5 19.4 137.9 

Race/Ethnicity/Nativity 

     

White Non-Hispanic – 

Native 

63.0 21.5 84.5 2.6 87.1 

Black Non-Hispanic – 

Native 

7.6  4.6 12.2 2.8 15.0 

Hispanic – Native 

2.5 

2.3 

4.8 

6.8 

11.6 

Other Non-Hispanic – 

Native 

0.8 1.0 1.8 1.2 3.0 

Hispanic – Foreign Born 

1.8 

4.5 

6.3 

2.8 

9.1 

Non-Hispanic – Foreign 

Born 

4.1 4.8 8.9 3.3 12.2 

Total 

79.8  38.7 118.5 19.4 137.9 

Summary 

     

Native White Workers 25 - 

54 

50.8 19.3 70.1 -7.7 62.4 

Native White Workers 55 

& Over 

12.2  2.2  14.4 10.3 24.7 

Workers of Color 25 – 54 

9.4 

7.3 

16.7 

7.7 

24.4 

Workers of Color 55 & 

Over 

1.6 0.5 2.1 3.0 5.1 

Foreign 

Born 

Workers  5.9  9.4 15.3 6.0 21.3 

Total 

79.8  38.7 118.5 19.4 137.9 

Source: Ellwood (2001) 

 

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