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Online Tools for Skeptical Fact Checking

Media Mind

Tamar Wilner

August 24, 2015

Changes to the media over the past few decades have brought many distressing trends. Social media tend to reward emotional manipulation over truth-telling. News outlets, even well respected ones, rush to publish rumors and poorly substantiated claims. The fragmentation of news into ideological islands and search engines’ tendency to cater to our preferences have helped to polarize viewpoints.

But while we’re arguably awash in more misinformation than ever before, online media have also enabled tools and sources that help us evaluate dubious claims. I recently spoke at the Skeptic’s Toolbox, the annual skeptical workshop in Eugene, OR, about the variety of fact-checking tools available. It was less a lecture than a conversation, as the participants provided many of their own suggestions. While we can’t pretend to be comprehensive, our combined lists should provide a good starting point for your fact-checking needs.

What is “Fact Checking”?

There are a variety of ways to answer this question. One way to think of fact checking is in light of its role in forming and evaluating arguments. As skeptics, we spend a lot of time looking for logical fallacies. But it takes more than sound logic for a conclusion to be true: the premises of the argument must be true as well or the entire argument falls apart.

We can investigate the soundness of our premises by examining internal consistency, external plausibility, and source validity.

The Fact-Checking Toolbox

Another way to think about fact checking is in terms of the tools at our disposal (all of which will also fulfill one or more of the roles above). I tend to think of these as a rough continuum, starting with the easiest types of checks, moving to the more involved. These categories are:

Internal Validity Checks

This basically boils down to being a critical reader. As you read a claim or article, look for features that can give you clues as to its reliability, such as:

This leads us to the easiest kind of source to evaluate: the fake news or satire sites.

Fake News and Satire Sites


Fake news sites have many aims. Some are cynical ploys to make as much money as possible off of “clickbait” headlines. Some purveyors of fake news seem to actually see themselves as doing a public service by exposing how gullible people can be. Some of the sites I list in this section are genuinely funny or satirical sites, like The Onion, that people have mistaken for real news; some claim the mantle of “satire” even though there’s really nothing humorous about them. (I’m looking at you, National Report, with your hilariously po-faced report that an entire Texas town had been quarantined due to Ebola.)

So Step 2 in your debunking process should always be to make sure the story you’re looking at isn’t simply fake. To help, here’s a list of fake and satirical news

But remember that new fake sites pop up all the time. Don’t see the site you’re evaluating on this list? Here are some things to try:

Finally, if a story mentions “Paul Horner,” run like the hills—he’s a fake news maven (founder of News Examiner, contributor to National Report) who likes to insert himself in stories.

Fact-Checking Sites

The next stage is to see if someone has already debunked the story or claim. If the debunking site you use is reliable, I see no shame in this—there’s plenty of bullshit out there for us all to investigate, without repeating someone’s else’s work.

Of course, that “if” is important. Even serious news sites that we generally trust can get a story dead wrong. I therefore limit my definition of “fact-checking sites” only to dedicated organizations whose raison d’etre is to thoroughly investigate claims, and who have a track record of doing so well.

Fact checking has really picked up steam as a movement within political reporting: There are now sixety-four sites around the world active in political fact checking, compared to forty-four a year ago.[5] Today in the United States, there are over two dozen fact checking organizations, though fact checking of national politics is dominated by the big three organizations:, the Washington Post Fact Checker, and PolitiFact, which has affiliates in several states. These are great places to check on claims made by politicians.

But fact checking occurs in other realms too. Here are a few of my favorite fact-checking websites:

screenshot of Headline: Fiorina's Fuzzy Vaccine Claims


This site was launched about six months ago by, which is based at the University of Pennsylvania. SciCheck focuses on addressing scientific claims that are made within the political arena. They can’t get to every such claim, of course, but if the claim you’re checking falls in this arena, SciCheck is certainly worth a look.

screenshot of @FakeAstropix showing very large moon over New York City. Tweet: Lunar Inflation! It's much too big! Do some trigonometry and check!


Fake photos are a big problem online. People will post a picture of one thing claiming that it depicts something else; or Photoshop a photo to depict something that never was; or circulate a picture without proper attribution. There are Twitter accounts devoted to sharing pictures without any regard for whether the images are actually real. Fake astronomy pictures (such as those ever-present giant moons) seem to be a popular category, and to counteract that we have the fine folks at @FakeAstropix, a Twitter account. Another good Twitter account, focusing on fake pictures of all sorts, is Pic Pedant.

screenshot of Health News Review showing navigation and featured stories

Health News Review

I really like this site, run out the University of Minnesota, which tries to address the very real and pressing problem of terrible health reporting. Health News Review has a team of over forty reviewers, mostly medical professionals, who grade mainstream health news articles against ten criteria—things like: Does the article engage in disease-mongering? Does the article discuss the costs of the proposed intervention? Was the study in question done on mice rather than humans? They spell all this out for the reader and they give the article a rating.

Other fact-checking sites:

Hoax Slayer
Antiviral (Gawker) - note that Antiviral posts from April 2014 and before are available here.
What Was Fake on the Internet This Week (Washington Post)
Sense About Science: For the Record
Emergent: Sadly, this site is no longer active, but since hoaxes tend to crop up again and again, there’s a good chance what you’re trying to debunk may be listed here.

The following sites do excellent fact checks, though it’s not all that they do; use their menus or search functions to see if they’ve fact checked the claim you’re interested in.[6]

Science-Based Medicine
Bad Astronomy
Bad Science

Reference Sites

What if no one has debunked the claim already? There’s lots of reference sites that can help you check out the claim against an existing body of knowledge. It’s good to have a list of them at your fingertips, which is why my fellow Skeptic’s Toolbox attendees and I brainstormed the items below.

But the scope of human knowledge is vast, and sometimes a reference that works great for one type of claim just doesn’t help on another. What are some good general principles for finding reference works?

My top tip is to be creative with your Googling. Rethink the aim of your search, and the various ways the desired information may be presented. For example:

One more note on finding good references: while Wikipedia should never be treated as a primary source, its footnotes are actually a great way to find works that you can rely upon.

Here are some reference sites to try, grouped loosely by category.[7]


Quackwatch has a wealth of information—including lists of further great resources. Check out their lists of “Comprehensive Medical Sites,” “Specialized Information Indexes” (click and scroll down a bit), “Interesting Web Sites.”
Cochrane Library (database of systematic reviews)
Science-Based Medicine (overviews and resource links for acupuncture, vaccines/autism and more)
Mayo Clinic (personal health information)
PubMed (medical studies)
Dietary Supplement Label Database - National Institutes of Health
Physician’s Desk Reference (prescription drug information)

Other science and math:

Skeptical Science (all about climate change)
Science Reference Services - Library of Congress (a list of reference guides, by subject)
Institute of Physics (search across a suite of pre-reviewed sites)
PLOS ONE (open access journals)
Dino Directory (identifying dinosaurs!)[8]

Other topics: (a knowledge-focused search engine that looks across thousands of pre-approved sources, including universities, governments, and non-profits, on any academic topic imaginable)
Journalist’s Resource (curated studies on a variety of topics)
Oxford English Dictionary (can be accessed from libraries)
OneLook (search across over 1,000 dictionaries)
Google Ngram (see how use of a phrase has changed over time)
CIA World Factbook (facts about countries)
Global Edge (statistical information about countries, and business stats by state, industry and more)[9]
National Security Archive (declassified U.S. government documents, hosted by George Washington University)
Sourcebook of Criminal Justice Statistics[10]
U.S. Census Bureau: Economic Indicators
Bureau of Labor Statistics: Labor Force Statistics and Charity Navigator (info on charities)
Khan Academy (videos on math, science, art history, and more)
Internet Archive “Wayback Machine” (see caches of websites saved earlier)[11]
AMBER Alert Program (list of active alerts, from the National Center for Missing & Exploited Children)[12]


What happens when can’t check a claim against a database of facts, but have to compare the claim against reality yourself? This is often the case when it comes to photos, videos, and claims made on social media.

When you want to check out the veracity of a photo, there are a few key questions to ask:

Further questions that might help to ask are:

As with text, you can save yourself grief by first going to fact-checking sites (see above) to see if someone has already debunked the photo.

Google Image Search screenshot with reverse image search button circled

After that, your next step should be a reverse image search to see where else the image has appeared. To use these sites, you can upload an image or enter its URL. (The URL should be for the image itself, not a website containing the image.)

Key tools for this are:

Next, try one of several tools that will check the image’s EXIF data to tell you the date and time the photo was taken and modified. These tools can also tell you what kind of camera was used, camera settings employed, and sometimes GPS location. These tools can, however, have trouble with social media sites, which strip out a lot of metadata.

Key tools:

Then you can do more detailed work using tools that examine the photo file itself, to determine when it was taken and look for alterations. Some of these tools have a bit of a learning curve.

The tools include:


There are a few tools to help you with video. YouTube Data Viewer gives you the upload time of a video and can help find earlier versions of the same video, using a reverse image search. If you need to slow down or brighten a video to try and make out certain features within it, try Tracker and VLC Media Player.

Originality Checks

It’s often important to see if the text you’re looking at has been copied from another source. For example, Googling text from badly written science articles can often turn up the original press release. Anti-plagiarism tools like Turnitin are also useful for this purpose. (You might need to sweet-talk an academic friend in order to access this tool.)

Verifying People

Google Image Search screenshot with reverse image search button circledThe logo for Bot or Not

If you’re looking at a post on social media, you may need to ask about the poster:

Some of these checks don’t even require wheeling out special tools. For example, if you’re looking at a social media account of a supposed public figure, does the account have a blue “verified” tag? (If so, hover over the check mark with your mouse to see if the text “verified account” pops up.) When was it created? (Very recently created accounts are a good sign of a hoax.)

Some of the tools you can use are:

Finally, sometimes you may even want to reach out to someone in real life, but can’t find contact details. Or you have a number, but need their name.

These services will help you do that:

Further Resources

Verification Handbook cover

If you’re hungry for more fact-checking help, here are some resources you might find useful:

The Verification Handbook - This resource, edited by Craig Silverman, is designed for journalists. But don’t let that stop you; it’s got loads of handy tips, case studies of fact-checking tools at work, and deeper explanations of some of the tools described above.
Skeptools - A blog by Tim Farley, with excellent examples of how to use fact-checking tools.
Verification Junkie - A listing of verification tools, maintained by journalism foundation executive Josh Stearns.
Fact-checking resources - A guide I wrote for the Fact-Checking Project of the American Press Institute. It goes into more detail on some of the social media tools above, and also gives resources for several hot-button political issues.

I hope you’ve found this overview helpful. To my mind, the project of cataloguing reliable online sources is an important one—but one that is just beginning. What are your favorite fact-checking tools and resources?




[4] Skeptics’ Toolbox participant suggestions


[6] Skeptics’ Toolbox participant suggestions

[7] Thanks again to Skeptics’ Toolbox participants for their suggestions, incorporated here.




[11] Tim Farley has a nice overview of how this and similar tools can be used:


[13] Chu, Z., Gianvecchio, S., Wang, H., and Jajodia, S. (2010). Who is tweeting on Twitter: Human, bot or cyborg? Proceedings of the 26th Annual Computer Security Applications Conference (pp. 21-30). Austin, Texas.

Tamar Wilner

Tamar Wilner's photo

Tamar Wilner is a Dallas-based journalist, researcher, and communications graduate student, specializing in the study of misinformation and science communication. She's a frequent contributor to the Columbia Journalism Review and a consultant on the Fact-Checking Project at the American Press Institute. You can find her at and on Twitter at @tamarwilner.