Statistics about the likelihood of sex offenders to re-offend took center stage during U.S. Supreme Court oral arguments Feb. 27 (Packingham v. North Carolina, U.S., 15-1194, argued 2/27/17).

The case concerned a North Carolina law prohibiting registered sex offenders from visiting social media and other websites like Facebook, YouTube and NYTimes.com.

But much of the debate focused on a hotly contested statistic highlighted in two Supreme Court opinions, Carissa Hessick—a law professor at the University of North Carolina, Chapel Hill, N.C., whose research focuses on criminal sentencing, criminal law and child pornography—told Bloomberg BNA.

Multiple studies from...