This seems a little like nitpicking. Interested parties file briefs with the court, and opposing parties can also file a brief with the court. It appears that

This seems a little like nitpicking. Interested parties file briefs with the court, and opposing parties can also file a brief with the court. It appears that none of the errors are so grave that they should change the ruling of the court. This is good, a ruling should be robust towards a slight changing of the statistics. Statistics change often, but the underlying trends are more stable. Here are two examples from the article: 1. The NASA v. Nelson opinion wrote that 88% of private employers conduct background checks of their employees. The 88% number wasn't in any of the briefs filed with the court, but they did find in the briefs that 74% of employers surveyed conduct criminal background checks. Okay, the court got the number wrong, but clearly background checks are a common practice among private employers. Nothing damages the decision. 2. In the US v. Windsor the opinion states that most states permit first cousins to marry. Most states would imply that >=26 states permit first cousins to marry. In fact, 19 states permit first cousins to marry (restrictions are common). So the court got that fact wrong, but 19 states is still a sizeable portion of the states, indicating that permitting first cousins to marry is not uncommon (first cousins actually getting married is uncommon though). So again, the general point still stands. While I think it would be nice to have fact checkers, the ability for opposing parties to file briefs with their own correct numbers is a pretty good deterrence against people lying to the court. I think in a lot of these cases, the opposing parties thought, "well, that number isn't right, but I'm not going to try the justices' patience by making them change that 11 to a 12."