Sometimes when a number seems like an outlier, it’s not an outlier — it’s wrong.

Last week, the St. Louis County Election Board reported that 3,287 people in Ferguson, Missouri, had registered to vote since the fatal shooting of Michael Brown in early August. I wrote at the time that “Ferguson’s 3,287 new registrants (in two months) is more than recorded by any township in St. Louis County in any midterm election since 2002.”

On Tuesday, the Democratic leader of the St. Louis County Board of Election Comissioners said, “Turns out that was an incorrect report that we were using.” According to an article by Jessica Lussenhop at Missouri’s Riverfront Times, the initial number reported was the “total number of interactions with Ferguson residents that had anything to do with their voter registration, so that included changes of address and other alterations to records.” The actual number of new registrants from Aug. 9 to Oct. 6 totaled just 128. That’s a little less than 4 percent of the original figure reported by the board.

Election analysts, such as myself, usually rely on official sources such as a secretary of state’s office or a board of elections. It’s where votes are counted and elections are decided. In retrospect, however, we probably should have known the original number was off.

There are about 21,000 people in Ferguson, according to the U.S. Census Bureau. Only about 15,000 Ferguson residents are of voting age. And according to the St. Louis County Election Board, there were 13,635 active registered voters in Ferguson at the end of 2012. In other words, the difference between the number of people of voting age in Ferguson and the number of registered voters is far less than 3,287. It’s only about 1,500. That alone should have made us suspicious of the initial report.

Additionally, the original number was so different from anything we had seen in the past. In Ferguson Township, which has double the population of the city of Ferguson, there had never been a midterm that saw even half the increase in registrations that was claimed in the past two months in the city of Ferguson.

The 128 number looks much more realistic. And the mistake is a reminder that we should all be a little less credulous.