Oxford Dictionaries recently chose “post-truth” as its international word of the year. The spread of fake news on Facebook helped propel Donald Trump to victory. And mainstream news organizations are grappling with questions about balance and calling out political candidates’ lies.

Into this fraught environment comes a new report from the Reuters Institute for the Study of Journalism, which takes a look at the growth of fact-checking sites in Europe: Over the last decade, more than 50 “dedicated fact-checking outlets” have launched across the continent. Worldwide, meanwhile, there are 113 active fact-checking groups; about 50 of those launched in the last two years.

The report’s authors, Lucas Graves and Federica Cherubini, conducted interviews and did an online survey of fact-checking sites across European countries. Among their findings:

— “The legacy news media remain the dominant source of political fact-checking” — but that’s especially true in Western Europe. “In the East and the South, meanwhile, the practice is less a supplement to conventional journalism than an alternative to it, based almost entirely in NGOs and alternative media outlets.” For example:

In the Balkans, for instance, a network of NGOs founded in the wake of civil conflicts in the 1990s has turned its attention to fact-checking over the past several years. Serbia’s Istinomer, or ‘truth-o-meter,’ a fact-checking and promise-tracking site modeled on PolitiFact, was established in 2009 by the Center for Research, Transparency and Accountability (CRTA)…Through organizational links and common funders — especially the National Endowment for Democracy — sister sites quickly spread across the region: Istinomjer, a project of Bosnia’s Zašto ne? (Why Not?), a peace-building group begun by student activists in 2002; Vistinomer, from the Macedonian NGO Metamorphosis, which began as an Open Society Foundations affiliate in 1999; and most recently Faktograf, by Croatia’s GONG, originally founded in 1997 as a citizens’ election-monitoring group. ‘The truth-o-meter was the glue for our network,’ said Dušan Jordovi, a CRTA project manager and one of Istinomer’s creators.

— “At established news organizations fact-checking is often tied to data journalism efforts.” Le Monde’s Les Décodeurs, for instance, started out as a two-person blog “but now manages a staff of ten producing roughly 15 fact-checks per month…the operation has evolved into the newspaper’s data journalism hub, and includes political reporters but also web developers and data specialists who produce the interactive charts and graphics the site is known for.”

— Many European fact-checking organizations, particularly those in the Balkans and the former Soviet Union, tie fact-checking into an agenda of political reform. “We don’t see ourselves as journalists, because we are not. But we are trying to contribute to the journalistic scene in Turkey by providing fact-based content,” said Baybars Örsek, a founder of Turkey’s Doğruluk Payı.

— “In our survey, half of European fact-checking outlets indicated that they relied on the news media heavily (four or more on a scale of five) to increase the reach and impact of their fact-checking.” This is problematic when the mainstream media in your country is partisan:

In media environments dominated by partisan outlets, factcheckers worried that their reputation would be stained by journalists who distort their work or cite it selectively. For instance, Bosnia’s Istinomjer has seen its articles selectively edited and reprinted by a newspaper owned by a party leader. “That was really potentially harmful for us,” said Aida Ajanovi. “It made an impression like we were actually working for the paper because they would give us like the middle two pages…And in a very consistent manner, they omit all the things written about the party that owns this paper.” In Macedonia, soon after Vistinomer launched, one opposition party unveiled a truth-o-meter that looked suspiciously similar but only fact-checked the ruling party.

Several fact-checkers complained that their work is sensationalized or misrepresented by journalists. “For the media to make it interesting they always use the term ‘lie,'” said Zdeněk Jirsa of the Czech site Demagog. “Then basically we have to write some sort of response, and clarify [that] we are not saying that the politician is lying, we are just purely stating that a fact is untrue.” Another widespread concern is that news outlets take material without fully crediting the fact-checkers who produced it. “There’s a lot of ripping off,” said Alexios Mantzarlis [the director and editor of Poynter’s International Fact-Checking Network]. “The better stories would end up on La Stampa even with scarce attribution.” He recalled an instance in which Pagella Politica debunked a far-right claim that authorities were removing a piece of playground equipment shaped like a pig because it offended Muslim mothers, only to see their reporting, and their carefully verified photo of the playground, spread across Italian media. Practitioners in Serbia, Poland, Romania, and elsewhere agreed. “Basically what happens in Kosovo, because it’s such a fragile system, what all the media outlets do is they steal our news,” said Faik Ispahiu. “It is a kind of flattery, but it is very frustrating.”

— Measuring impact can be difficult. (“No one ever corrected themselves on the basis of what we wrote,” said Alisa Karović, of Bosnia’s Istinomjer.)

“Though fact-checkers are the first to admit their work rarely has a dramatic impact,” said the report’s lead author Graves, “evidence suggests that fact-checking can help to dispel misinformation and inhibit political lying.”

The full report is here.