Michigan's own statistical wunderkind Nate Silver comes to the defense, sorta, of Chief Justice Roberts' controversial use of statistics in oral argument questioning in Shelby County v. Holder, the challenge to section 5 of the Voting Rights Act. As a reminder, Section 5 requires that certain states, counties and townships with a history of racial discrimination get pre-clearance from the Department of Justice before making changing their voting laws. Here's the key exchange:
- CHIEF JUSTICE ROBERTS: Just to get the -- do you know which State has the worst ratio of white voter turnout to African American voter turnout?
- GENERAL VERRILLI: I do not.
- CHIEF JUSTICE ROBERTS: Massachusetts. Do you know what has the best, where African American turnout actually exceeds white turnout? Mississippi.
- GENERAL VERRILLI: Yes, Mr. Chief Justice.
- But Congress recognized that expressly in the findingswhen it reauthorized the act in 2006. It said that the first generation problems had been largely dealt with, but there persisted significant --
- CHIEF JUSTICE ROBERTS: Which State has the greatest disparity in registration between white and African American?
- GENERAL VERRILLI: I do not know that.
- CHIEF JUSTICE ROBERTS: Massachusetts. Third is Mississippi, where again the African American registration rate is higher than the white registration rate.
In his FiveThirtyEight blog in the New York Times, Silver says:
As much as it pleases me to see statistical data introduced in the Supreme Court, the act of citing statistical factoids is not the same thing as drawing sound inferences from them. If I were the lawyer defending the Voting Rights Act, I would have responded with two queries to Chief Justice Roberts. First, are Mississippi and Massachusetts representative of a broader trend: do states covered by Section 5 in fact have higher rates of black turnout on a consistent basis? And second, what if anything does this demonstrate about the efficacy of the Voting Rights Act?
As to whether the Chief Justice misconstrued the data, Silver demurs:
If he meant to suggest that states covered by Section 5 consistently have better black turnout rates than those that aren’t covered by the statute, then his claim is especially dubious. However, the evidence does support the more modest claim that black turnout is no worse in states covered by Section 5. There don’t seem to be consistent differences in turnout rates based on whether states are covered by Section 5 or not.
The bigger potential flaw with Chief Justice Roberts’s argument is not with the statistics he cites but with the conclusion he draws from them.