Evidence and Ideology

Americans are absolutely smitten with detective shows where justice triumphs after a painstaking collection and analysis of all available evidence. The popularity of these shows reflects—accurately, I think—America’s pragmatic culture, our desire to “get to the bottom of things” and to base decisions on hard evidence.


So how do we explain an American policy process that increasingly displays a positive contempt for evidence?


There are all sorts of examples: twenty-five years of research has overwhelmingly demonstrated that the drug war is a costly and counterproductive fiasco. Legislators have responded by waging our war on drugs more enthusiastically. We have scientific unanimity on the reality of global warming. Our elected officials “pooh-pooh” climate change. On July 19, the New York Times reported yet another case of the Administration’s “don’t confuse me with the facts” approach to federal legislation. Education Secretary Margaret Spellings joined several Congressional Republicans announcing a proposal to spend $100 million dollars on a school voucher “pilot project.”


Education vouchers are a policy near and dear to the hearts of the political right, albeit for different reasons: the Christian right wants tax dollars to support religious schools; libertarians see education as a consumer good to be provided by the market; and a sizable number of ordinary folks who have never been happy about junior sitting next to a black classmate see vouchers as a way to re-segregrate.


Except for those who are ideologically committed to them, vouchers don’t generate much political support among people satisfied with public school performance. However, it is undeniable that students at many public schools are not performing well. Voucher proponents thus argue that fairness requires sending children from failing public schools to private ones that are “better.”


The problem is, there is no evidence that private schools do a better job of educating the children who attend “failing” public schools. (Comparing kids whose parents are willing to spend the money to send them to private schools to kids whose parents often don’t even make the effort to see that they get to public school is not comparing apples to apples.) Most poorly-performing public schools have large populations of children who do not come prepared to learn: they are disproportionately poor, disproportionately from broken homes, often come to school hungry, and so forth. Before they can learn, these barriers must be addressed.  


The Department of Education decided to do what good detectives do: look at the evidence. The Department studied 725,000 children in public and private schools, controlling for student background, and discovered that—with the exception of a small difference in 8th grade reading scores—public school students did as well or better than those in private schools. Secretary Spelling later said she didn’t know about the study her own department had conducted, and a Department underling dismissed it as “a technical analysis.”


On TV, when the DNA evidence exonerates our suspect, we look for the guy who really committed the crime. In Washington, when evidence undermines our ideology, we ignore it.