Fact checking works: results from a new international study

13 September 2021 | Team Full Fact

Over the last ten years, fact checking has grown around the world.

As part of our work we’ve seen many examples of how good, timely information can change debate—and lives—for the better.

We’ve also conducted research to help improve and focus our efforts—around health misinformation, for example.  

But as the work of fact checkers has grown more visible, the global evidence base on the impact of fact checking hasn’t kept up. 

A few years ago Full Fact, Africa Check and Chequeado along with two academics Ethan Porter (George Washington University) and Thomas Wood (Ohio State University), decided to change that. Ethan and Tom devised an experiment to see if fact checking actually works, and whether its effects are long lasting. With funding and support from Luminate and Institute for Data, Democracy & Politics we put the experiment into practice.

This was the first time such a study on fact checking had been done simultaneously on three continents, so we needed help. We also worked with YouGov and Ipsos Mori to handle fieldwork and data collection.

We decided to write up the findings no matter what the outcome. 

Running the study

We took a selection of fact checks and put them in front of people in the UK, Argentina, South Africa and Nigeria to see if it changed their minds.

Those included checks on topics such as Covid-19, climate change, and the economy.

We then went back to the same people approximately two weeks later to see if it still had an effect. 

We were nervous. There was every chance the results would show that fact checking wasn’t having the impact on bad information that we’d hoped.

That wasn’t the case. We’re delighted to share the results, published in a leading journal, Proceedings of the National Academy of Sciences.

What the study found

In short: fact checking works.

On average fact checks reduced belief in misinformation.

This is true across different countries, cultures, and political environments. 

People who were presented with fact checks retained factual information for weeks afterwards.

And fact checking increased accurate beliefs regardless of political affiliation, a trend that held firm regardless of how politically salient the topic: we tested checks covering climate change and the pandemic. 

Read the full paper

Coming off the back of a year where we’ve seen bad information threaten lives, this study shows the difference fact checking can make.

As a result of the work of organisations including Full Fact, more people are able to recognise false claims and make decisions based on good, reliable information.

We’re incredibly grateful to all those who worked on this project and give to support our work. We hope you’re as encouraged by these results as we are.


Full Fact fights bad information

Bad information ruins lives. It promotes hate, damages people’s health, and hurts democracy. You deserve better.