Spelling Creator

Fact checking ​

A lesson states facts the speller is then asked about: how tall Everest is, when the Eiffel Tower went up, how many people live in Paris, how much a cat weighs. Fact checking compares the numbers, dates and names in your passages with three sources:

Sources can be out of date or wrong too, so treat what it finds as things to look into, not verdicts.

Running a check ​

Open Check lesson (the Check button in the editor's top bar) and scroll to the Facts section at the bottom. Press Check facts. After the usual verification check, gray placeholder lines show while the check runs, then you see:

  • Facts a source disagrees with, grouped by section. Each reads like "8,000 METERS": Wikidata gives the height of Mount Everest as 8,848.86 meters. and, like any finding in the panel, takes you to its passage when you choose it. Under it is "Checked against" the Wikidata item it was compared with, its description and an Open on Wikidata link, because a name can match the wrong thing and you are the one who can tell. When the answer came from the Smithsonian or Wikipedia, a second link (Open the volcano's record or Open the article) opens that page too.
  • A count of the rest, behind Show N more: facts that matched, and facts that couldn't be checked. A fact that couldn't be checked isn't a problem, only a gap in the sources: no item by that name, no source with a value, a unit the check can't convert, a fact about a kind of animal that didn't match, or a source that didn't answer. A match from Wikipedia quotes the article's sentence, so you can see it says what your passage says.

The result is a snapshot. When you change the words a fact was found in, that fact drops off the list and is counted under "N facts have changed in the lesson since this check", so fixing a number clears its finding without checking again. Closing the panel to go to a finding keeps the result. Check again runs a fresh check.

Nothing it finds blocks anything, and none of it is counted in the Check button's number or the outline: those are always current, and this is a snapshot you asked for.

The Facts section only appears when the Spelling Creator site you're using has AI set up. Your passages are sent to that site's server, and an AI service lists the facts in them. The AI never decides whether a fact is right: that is done by comparing with the sources, and a fact whose words aren't actually in your passage is thrown away.

What can be checked ​

Numbers, dates and names stated about one specific, named thing:

  • Sizes and amounts: height, height above sea level, length, width, depth, diameter, radius, area, volume, population, mass, speed and temperature.
  • Space: distance from Earth, average distance from what something orbits, and the time to go once around its orbit.
  • Dates: when someone was born or died; when something was built, founded, started, ended, happened, discovered or released; a volcano's last eruption, or any one eruption.
  • Names: a capital, the country, continent or region something is in, an official language, a currency, a country's current leader, who discovered or invented something, who made it, what it is named after, and where a river flows into.
  • Kinds of animal: how big, heavy, long, tall or fast they are, how long they live, how long they are pregnant, and how many young they have.

Metric and imperial units all work, as do temperatures in Celsius, Fahrenheit and kelvin, durations from seconds to thousands of years, astronomical units, light-years and Earth masses. Findings quote the source in the unit your passage uses: a passage in feet is told "29,031.69 feet", not "8,848.86 meters".

What counts as agreeing ​

A passage rounds, and a source often holds several honest answers at once, so "agrees" is deliberately generous and "disagrees" means something.

  • Any source agreeing is enough. A fact only disagrees when a source has a value, none agrees, and every source asked actually answered.
  • Every current value counts. Everest is listed as 8,848, 8,848.86 and 8,850 meters; the Eiffel Tower was started in 1887 and opened in 1889. A passage using any of them is not wrong.
  • Values that have ended don't count. Melbourne was Australia's capital until 1927, so a passage saying it still is disagrees. The same goes for former prime ministers and the height of a building that has been knocked down.
  • A name agrees when it's one of the current answers. The Nile flows through several countries, and a passage naming any one of them is right. Short names work too: "USA" finds the United States.
  • For dated figures, only the latest counts. A population is compared with the most recent count, and the finding says which year it is from ("2,103,778 as of 2023"). A passage that agrees with a 1910 census is out of date, not right.
  • A figure gets the rounding it was written with, plus a little more. "9,000 meters" allows 500 either way; "8,849" allows half a meter. On top of that, 2% of the source's value, or 10% when the passage hedges ("about", "nearly").
  • "More than", "less than" and "up to" are limits, not rounded figures, so "more than 10,000 meters" disagrees with Everest. "Grows up to 2 meters long" is true of anything 2 meters or under.
  • Dates are compared as precisely as the source knows them. A date known to the day is checked to the day, if your passage gives one.

Kinds of animals ​

"Cats weigh about 4 kg" is true of a typical cat and false of plenty of real ones, and the sources' figures for animals are patchy. So a fact about how big, heavy or fast a kind of animal is, how long it lives, or its young can be confirmed but is never called wrong. When a source's figure doesn't match, the finding still tells you what it says: "20 YEARS": Wikidata gives the lifespan of cat as 15 years. Animals vary, so this isn't counted as wrong.

Facts that don't change from one animal to the next, like when a species was discovered or who it is named after, are checked as for anything else, and can be wrong.

Volcanoes ​

The Global Volcanism Program keeps the standard record of the world's volcanoes active in roughly the last 12,000 years, with every dated eruption, and keeps it current.

  • Height is compared with the summit's height, alongside Wikidata's.
  • "Last erupted" is compared with the latest eruption, anywhere from its start to its end: "Mount St. Helens last erupted in 2004" and "in 2008" are both right.
  • "Erupted in" agrees with any eruption the date falls in, allowing for how uncertain the eruption's own date is.
  • Older eruptions are treated carefully. Before a volcano's eruptions were written down as they happened, the record has gaps, so a date there that matches nothing is left as "couldn't be checked", not called wrong. Before the year 1583 only the year is compared: the traditional date of the eruption that buried Pompeii is 24 August 79, while the record now says October, and a passage saying August isn't flagged.

Wikipedia ​

When the other sources can't settle a fact, the check reads the subject's English Wikipedia article and looks for a sentence that says the same thing, about the same property. A match turns the fact into a match and quotes the sentence ("4 KG" matches Wikipedia, which says: Adult domestic cats typically weigh 4-5 kg (8.8-11.0 lb).) so you can judge it yourself. Wikipedia can only ever confirm a fact: not finding something in an article proves nothing.

When it picks the wrong thing ​

A name can mean several things: Georgia the country or the state, Mercury the planet or the element. The check uses a word or two about what the thing is to pick, and usually gets it right, but when it doesn't, the finding says so plainly ("Checked against Georgia (state of the United States)"). That's why the item it used is always shown.

What it doesn't do ​

  • Facts that aren't a number, a date or a name ("the Nile flows north") aren't checked.
  • Facts about a whole kind of thing, other than the animal facts above, are left out: "octopuses have three hearts" and "cats sleep 16 hours a day" aren't values any of these sources hold.
  • Numbers in a made-up story or a word problem are left out.
  • It doesn't change your lesson. Every finding is for you to look at.

Limits ​

A check reads up to 60 passages and up to 40 facts. Checking the same text again within a week gives the same answer straight away without counting toward the per-minute limit on AI requests. A check where a source couldn't be reached isn't remembered, so you can try again later.

For how fact checking works in the code, see the developer notes.

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