Does the WIC program meet "assignment based pm a cutoff value on a preprogram measure"?
Are
all persons on one side of the cutoff are assigned to one group? Yes, women with low income and "nutritional risk" are enrolled
in WIC.
Are
all persons on the other side of the cutoff are assigned to the other group? Yes, women not meeting the criteria are not enrolled in WIC.
Is
there a continuous quantitative preprogram measure? Yes,
women are assigned based on low income (185% of the poverty line). The amount (in dollars)
is a continuous quantitative preprogram measure. Birthweight, the outcome of interest, is
a continuous quantitative postprogram measure.
What are some of the advantages of using the for an evaluation of the WIC program? (Remember internal validity and ethics)
Program participants are
assigned to groups based on cutoff criteria (low income and nutritional risk).
A well-implemented RD
design is comparable in internal validity to conclusions from randomized experiments.
From an ethical
perspective, RD gets the program to those most in need. It is not necessary to deny the
program for some pregnant women who meet the criteria simply for the sake of a scientific
test.
An RD design could point
out whether or not the program assignment is really based on the established
criteria. This is important for accountability.
What are some of the disadvantages?
In practice, the
criteria, particularly "nutritional risk" may not be defined in the same way at
all WIC sites in NY state or for all individuals at a single WIC site. This would
create a "fuzzy" design.
In sum, the main advantage of the RD design in this "case study" is for both ethical and practical (program improvement, accountability) reasons.
I hope this increased your understanding of the RD design (or at least raised awareness of the complexities in the 'real world').
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