Social media platforms have come to define the modern digital world -- and the real world it’s meant to represent. We turn to these platforms for news, to interact with elected officials, to catch up with friends and to converse with the greater world beyond our own. Yet these platforms are not neutral forums. They actively intervene to remove speech with which they disagree. Increasingly, they also turn to a small number of fact-checking websites to arbitrate what constitutes “truth,” placing a small number of people in charge of, essentially, defining reality.

To vet the news stories shared by its more than 2 billion users, Facebook relies on just 54 organizations, in 38 countries, that must render one of nine verdicts for each article. A story deemed to be false is penalized to “significantly reduce the number of people who see it,” according to Facebook, while repeat offenders “have their distribution reduced … their ability to monetize and advertise removed and their ability to register as a news Page removed.”

A small number of fact-checking organizations thus wield enormous power over news organizations. In contrast to the tens of thousands of moderators employed by social media companies to enforce their speech rules, the fact-checking organizations they rely upon employ only a small, often token, workforce with the power to define truth itself.

Over the past three months, the RealClearPolitics Fact Check Review has monitored 222 claims on topics of civic or public concern from major U.S. fact-checking sites PolitiFact, Snopes, FactCheck.org, the New York Times and the Washington Post. Combined, a total of 69 individuals reviewed those claims, working out to an average of 2.2 claims per person for PolitiFact and the Washington Post, four per person for FactCheck.org, nine for Snopes and 11 for the Times.

In reality, some fact-checkers account for more claim reviews than others. Of 11 relevant Washington Post claim reviews, Glenn Kessler was responsible for eight, while for the Times, Linda Qiu was responsible for all 11. Of Snopes’ 55 relevant claim reviews, just two fact-checkers (Dan Evon and Bethania Palma) accounted for more than half of them over the last three months.

In short, fact-checking outlets are not like newsrooms with dozens or even hundreds of staffers. They are very small organizations with just a handful of fact-checkers; sometimes just one or two individuals are responsible for the majority of the output. This means that the power to decide what constitutes truth is centralized in the hands of a very small number of people.

Explore the Fact Check Review yourself and see just how this dynamic plays out.

Correction: An earlier version of this article erroneously stated that The Washington Post, New York Times and Snopes are Facebook fact-checking partners.