From Neurons to Neighborhoods The Science of Early Childhood Development (2000) / Chapter Skim
Currently Skimming:
Pages 71-89
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 71... ...
Indeed, the richness of developmental science derives from the field's reliance on multiple methods of inquiry, and its greatest insights often emerge at the convergence of diverse strands of evidence. We begin by considering causal inference in basic and applied developmental research.
|
From page 72... ...
To be quite specific, random assignment would ensure that the probability of assignment to high-quality or low-quality care is utterly unaffected by any preexisting characteristic of the child.1 1 Some have argued that random assignment eliminates selection bias only in large samples, but this is not true. By ensuring that previous variables are unrelated to the probability of assignment to each treatment condition, random assignment ensures that tests of statistical significance accurately quantify the uncertainty about the causal question.
|
From page 73... ...
2A possible scenario for experimentation arises when a large number of parents seek child care and only a small number of places in child care centers are available. Then children can be randomly assigned to receive child care or to be placed on a waiting list.
|
From page 74... ...
Selection bias is not an issue because comparisons are made within the same children. That is, the child's behavior when parents are providing the best care is compared with the same child's behavior when the parents are not doing such a good job.
|
From page 75... ...
Government-subsidized early childhood intervention programs, nutritional supplements, home visitation programs, and parent training programs are but a few examples. Program evaluations enable policy makers to assess how program funds are being spent, whether and to what extent programs are being implemented as planned, and, ultimately, whether program par
|
From page 76... ...
, the High/Scope Project (Schweinhart et al., 1993: see Chanter 13) study of the On-term ettects ot high-quality child care, the Abecedarian program t~ampoe~ ana Haney, 1994, 1995)
|
From page 77... ...
Thus, in longitudinal evaluations, "differential attrition" arises and selection bias remains a problem despite efforts to conduct a randomized experiment. Even in these cases, however, it is important to keep in mind that the
|
From page 78... ...
Even when a randomized experiment is impossible or unadvisable, however, "experimental thinking" is central to success of causal or comparative studies. Nonexperimental evaluations of program impacts can be viewed as more or less accurate approximations of "the experiment we wish we could conduct but cannot." The more accurate the approximation, the stronger the confidence that the evaluation has produced a valid causal inference.
|
From page 79... ...
Such an analysis would use statistical procedures to control for extraneous variables. Yet participants with no chance or a very small chance of experiencing divorced parents or low birthweight or infant child care really contribute little or no useful information about the causal question of interest.
|
From page 80... ...
In research on early childhood interventions, the effectiveness of the intervention often depends on the knowIedge and skill of the practitioners those who provide home visits, child care, or parental counseling and on other services available in the community (see Olds et al., 1998b)
|
From page 81... ...
It is possible, for example, that seriously depressed women are less responsive to home visiting interventions. In this case, maternal depression moderates the treatment effect and it would be advisable to assess effects separately for depressed and nondepressed mothers.
|
From page 82... ...
82 FR OM NE UR ONS TO NEIGHB ORHO ODS inquiry on a common set of hypotheses in developmental research usually includes interesting variation in participants, implementers, sites, and treatment conceptions, as well as interesting variation in methodological approaches. Using meta-analysis, it is possible to exploit this variation to study intensively the degree of generalizability of a treatment effect and the specific sources of variation in the treatment effect.
|
From page 83... ...
the reliability with which one can distinguish among individuals at any given time. The study of cross-sectional individual differences, especially differences in cognitive functioning, has had a powerful and enduring influence on the theory and practice of measurement in psychology.
|
From page 84... ...
for vocabulary is a positively accelerating curve, as depicted in Figure 4-1. · A longitudinal study that is optimally designed to ensure a given level of statistical precision for the question at hand.
|
From page 85... ...
22 24 26 FIGURE 4-1 A sample of individual vocabulary growth trajectories. SOURCE: Huttenlocher et al., 1991.
|
From page 86... ...
In sum, it is often essential in studies of early childhood development to recognize that children are rapidly growing. Causal inference on aspects of child growth poses important issues that extend beyond efforts to make causal connections between an intervention and a set of child outcomes at a given age.
|
From page 87... ...
Its purpose has not been to assert the superiority of causal studies, but rather, when causal questions are being addressed by research, to illustrate the key issues that arise and the critical importance of being tough-minded about ensuring that the conditions for making valid causal inferences are met. Only when the limits of current knowledge and the best thinking about improved designs are clear can we plan research that will contribute significantly to knowledge in the future.
|
From page 89... ...
11 The Nature and Tasks of Early Development ween the first day of life and the first day of kinder -- - - -- -- -- -- ~,"1 ~11, development proceeds at a lightning pace like no other. Consider just a few of the transformations that occur during this S-year period: · The newborn's avid interest in staring at other babies turns into the capacity for cooperation, empathy, and friendship.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.