 of children’s health. A high mortality rate reflects negatively on the health of the overall population—including survivors—since it indicates poor overall conditions. This importance is dramatically illustrated by research showing that the narrowing of the black-white test score gap during the 1980s is best correlated with the decline in the mortality rate for black children as a result of the Civil Rights movement—specifically the integration of hospitals during the 1960s. The Civil Rights Act of 1964 and the Medicare Act of 1965 increased access to hospitals for black people living in the South and reduced deaths from pneumonia and diarrhea—both easily treated with adequate medical care—among young black children. Researchers used this reduction in the post-neonatal mortality rate as a proxy for overall early childhood health and found that it explained a significant increase in test scores when these children were in high school.
Measuring the economic impact of public policy
One of the most significant challenges in empirical research is separating causation from correlation. As a hypothetical example, a correlation between pollution and low birth weights does not necessarily prove that pollution causes low birth weights. This correlation might instead be the result of poor parents living in more polluted areas where housing is cheaper, and their children may have lower birth weights as a result of poverty. Pollution might not be causing low birth weights even though the two measures are correlated with each other if a third variable, such as poverty, is causing the variation in both birth weight and pollution in the surrounding environment.
Economists frequently measure the causal impact of environmental factors and public policy with natural experiments. These events approximate a classic laboratory experiment by exposing one group of people to a treatment while leaving a control group unaffected. For example, a study by Princeton University economist Janet Currie and University of California, Berkeley economist Reed Walker established that air pollution causes low birth weights by examining what happened after traffic congestion and automobile emissions declined near New Jersey toll plazas. Currie and Walker found that after the state introduced electronic highway tolls, or E-Z Pass, the ensuing reduction in automobile emissions reduced the incidence of prematurity and low birth weight among mothers who lived within two kilometers of a toll plaza. The 8.5 percent to 11.3 percent reduction was determined by comparing changes in birth weights of children near the toll plaza—the treatment group—and those farther away from the toll plaza—the control group. These and other natural experiments allow researchers to measure the causal effects of exposure to pollution, as well as access to health insurance or receipt of nutritional assistance.
The House budget includes $887 billion in cuts over 10 years from nondefense programs that Congress funds annually in appropriations bills. Most of these cuts are vague and unspecified reductions that Congress would have to make in future years, but the budget specifically targets the U.S. Environmental Protection Agency, or EPA, for budget cuts. And based on the House Appropriations Committee’s actions in earlier years, these cuts would also be likely to fall particularly hard on lead removal efforts.
Research on the effects of pollution on children’s health has especially focused on how reductions in pollution as a result of environmental regulation improve children’s health, since the introduction of new rules creates a natural experiment that allows researchers to measure causality. One study, for example, found that the Clean Air Act prevented between five and eight infant deaths per 100,000 live births for every a one-unit reduction in airborne particulates caused by the law. Another study found that a two standard deviation increase in two types of pollutants regulated by the EPA—heavy metal cadmium and toluene—increased the incidence of low birth weights by 1.2 percent to 2