What role should statistics of social play in judicial decision making? In Sykes v. United States, in order to determine whether a vehicular flight from the police is likely to be dangerous, the majority opinion from Justice Kennedy, as well as the concurring opinion from Justice Thomas, heavily relied on empirical data.

Justice Kennedy noted that “although statistics are not dispositive, here they confirm the commonsense conclusion that Indiana’s vehicular flight crime is a violent felony.” Justice Thomas wrote that “common experience and statistical evidence confirm the “potential risk” of intentional vehicular flight.”  Justice Kagan found that the data was inconclusive, but noted the “majority’s intuition that dangerous flights outstrip mere failures to stop—that the aggravated form of the activity is also the ordinary form—seems consistent with common sense and experience.”

Here, we have 8 Justices who have different views about statistical data supporting social costs from vehicular flight, but in large part due to “commonsense conclusions,” “common experience,” “intuition” and “common sense and experience,” they agree on the outcome. None of these statistics were even introduced at trial, or admitted into evidence. Should courts be able to take judicial notice of these statistics because they conform to common sense?

What is the proper role for courts to consider statistics and common sense to illustrate social costs, such as dangers from vehicular flight?

Justice Scalia, in dissent, disagreed with this reliance on statistics.

Today’s opinion then outdoes Chambers in the volume of statistics that it spews forth—statistics  . . . concerning injuries attributable to police pursuits, statistics from the Department of Justice concerning injuries attributable to burglaries . . .  statistics from the U. S. Fire Administration concerning injuries attributable to fires . . .  statistics . . . concerning injuries attributable to police pursuits. (citations omitted).

Scalia raised a very important point–statistics raised in briefs were not challenged in the typical adversarial process.

Supreme Court briefs are an inappropriate place to develop the key facts in a case. We normally give parties more robust protection, leaving important factual questions to district courts and juries aided by expert witnesses and the procedural protections of discovery . . . An adversarial process in the trial courts can identify flaws in the methodology of the studies that the parties put forward; here, we accept the studies’ findings on faith, without examining their methodology at all. The Court does not examine, for example, whether the police-pursuit data on which it relies is a representative sample of all vehicular flights. The data may be skewed towards the rare and riskier forms of flight.

Further, Scalia laments that courts are free to pick and choose which statistics they like–much like cherry-picking favorable legislative history–without any basis to disagree with them, based on no discernible reason other than “common sense.”

Scalia notes that these “untested judicial fact finding [are]  masquerading as statutory interpretation.”

The Court does not reveal why it chose one dataset over another. In sum, our statistical analysis in ACCA cases is untested judicial fact finding masquerading as statutory interpretation. Most of the statistics on which the Court relies today come from government funded studies, and did not make an appearance in this litigation until the Government’s merits brief to this Court.

So what is the proper role for courts to consider statistics and common sense to illustrate social costs, such as dangers from vehicular flight? As Scalia notes, courts are free to pick whatever statistics they want from a plethora of Brandeis Briefs submitted in every case. These statistics are not challenged in any adversarial process, and frequently stand in dispute. Most importantly, these facts were never introduced at the trial stage. Is this “Statutory Interpretation” or “Untested Judicial Fact Finding” in costume?

The relationship between statistics, common sense, and social costs takes on a higher degree of magnitude when adjudicating constitutional, rather than statutory, issues.

I have written about the selective reliance of statistics in the context of Second Amendment cases, focusing particularly on Justice Breyer’s one-sided reliance on statistics, in my article, The Constitutionality of Social Cost (which should drop in the Harvard Journal of Law & Public Policy in the next month or so),.

With respect to Justice Breyer’s opinion in Heller, I noted that “when [he] weighs a relatively one‐sided sample of studies discussing the dangerousness of guns against three restrained interests,it is unsurprising how that scale tilts.” Although Justice Breyer views gun control issues a“highly statistical matter,” the statistics he relies on are far from undisputed.

Justice Scalia affirmed this point during oral arguments in McDonald, in the process of disagreeing with Justice Breyer over the role of statistics in determining constitutional rights:

JUSTICE BREYER: There are two ways [to consider the firearm regulation]. One is that—look at—all you have to do is look at the briefs. Look at the statistics. You know, one sidesaysa million people killed by guns. Chicago says that their—their gun law has saved hundreds, including—and they havestatistics—including lots of women in domestic cases. Andthe other side disputes it. This is a highly statistical matter.. . . .

JUSTICE SCALIA: There’s a lot of statistical disagreement onwhether the Miranda rule saves lives or not, whether it results in the release of dangerous people who have confessed to their crime, but the confession can’t be used. We don’t—we don’tresolve questions like that on the basis of statistics, do we?

I agree with Scalia that although statistics are important “for the legislatures,”they are not important for “the judges.”

Depriving a person of a constitutional liberty, such as the right to keep and bear arms, based on disputed statistics is a flawed analysis. And Breyer’s statistics “show” that someone who has done absolutely nothing wrong, has taken no action other than applying for a permit, and has exhibited no propensity for violence–like Dick Heller or Otis McDonald, unlike Marcus Sykes who fled from the police–may cause harm in the future. This, among other reasons, has contributed in no small part to the currently disjointed state of Second Amendment jurisprudence.

Even the Brandeis Brief from Mueller v. Oregon was littered with controversial statistics, that ultimately proved to be totally false. And, in reliance of that Brief, the Court issued a decision that just about everyone today would disagree with.

More attention should be given to how appellate judges take judicial notice of statistics that were never challenged at the trial level. Statistics, as much as people may wish to believe, are not objective. Courts at the trial level recognize this when introducing evidence, and permit advocates to challenge them before admission. Appellate courts would be well-served to make similar determinations before basing statutory, and even constitutional decisions, on these statistics. Statistics are not evidence until they are admitted as evidence.

Cross-Posted at ConcurringOpinions.com.