Typing that when we mean than is a frequent typo partly because that is such a common word. And unlike teh, it’s a valid word and therefore less conspicuous. That is a background word, a bit player, typically only a part of some larger sense.
There are exceptions, times when that is brought to the foreground (“To be, or not to be, that is the question”), but it usually remains under our reading radar. So when it sneaks in where than rightfully belongs, its familiarity means it can easily go unnoticed.
Last October I wrote about this that-for-than typo, investigating among other things its typographic, mechanical, and phonetic aspects. Since then I’ve noticed it quite often, especially in informal writing but also in edited prose from reputable publishers and organisations.
Recently I was reading an article by David Crystal called “What is Standard English?” (PDF, 1.8 MB) when I came upon this passage:

The image is from the article as it appears in Concord (spelled Concorde on Mr Crystal’s website), apparently a biannual publication by the English Speaking Union. The typo does not appear in the same text in The Cambridge Encyclopedia of the English Language:

I don’t evangelise about any old typo, but I’m consistently impressed by this one’s ability to sneak past so many careful eyes. And, as I noticed when MobyLives mentioned the phenomenon, the instinct to correct it when it’s spotted is powerful too — even when the correctness is incorrect. If you’re a writer or editor, it’s one to watch out for.
Updates:
Further examples appear in the following books: Women, Fire, and Dangerous Things, by George Lakoff:

Green English, by Loreto Todd:

Beethoven, by J. W. N. Sullivan:

Southern Irish English, by Séamas Moylan:

Vex, Hex, Smash, Smooch, by Constance Hale (review copy, so it may have been spotted later):

Three times in Octavia Butler’s novel Fledgling:



Erik Davis’s Nomad Codes:

Séamas Ó Catháin’s The Bedside Book of Irish Folklore:

For Who the Bell Tolls, by David Marsh:

‘The Ballroom of Romance’, in The Distant Past by William Trevor:

When You Are Engulfed in Flames, by David Sedaris (Little, Brown, 2008)

Herman Koch, The Dinner:

Chris Cleave, The Other Hand:

Terence McKenna, The Archaic Revival:

Benedict Kiely, A Journey to the Seven Streams (title story):

Jimmy Burns, Hand of God: The Life of Diego Maradona:

Julia O’Faolain, ‘Chronic’, in Melancholy Baby:

Guns, Germs and Steel by Jared Diamond:

Sara Paretsky, ‘A Taste of Life’, in Reader, I Murdered Him, edited by Jen Green:
![Excerpt: 'You don't want to paint the first night your mother is in town,' Sylvia said archly, inviting Jerry to compare mother with daughter, indeed pausing for the expected remark ('You can't be her mother – if anything she looks older that [sic] you!') Jerry said nothing, but blushed more than ever.](https://stancarey.files.wordpress.com/2010/05/sara-paretsky-a-taste-of-life-in-jen-green-reader-i-murdered-him-that-than-typo.jpg?w=440&h=99)
Brewer’s Dictionary of Irish Phrase and Fable by Sean McMahon and Jo O’Donoghue:
!["CAB [Criminal Assets Bureau] collected more that [sic] €23 million in tax and interest charges in 2001."](https://stancarey.files.wordpress.com/2010/05/brewers-dictionary-of-irish-phrase-and-fable-that-than-typo.jpg?w=440&h=91)
George Lakoff, Don’t Think of an Elephant:
!["The aerial-delivery vehicles could not go more that [sic] a few hundred miles and could not threaten the United States."](https://stancarey.files.wordpress.com/2010/05/george-lakoff-dont-think-of-an-elephant-that-than.jpg?w=440&h=72)
Zadie Smith, Changing My Mind, quoting Kafka in translation:

Randy Allen Harris, The Linguistic Wars:

Jacek Hugo-Bader, White Fever, quoting the 1957 book Report from the Twenty-First Century:

Ryan Holmberg, The Translator Without Talent:

Julie Sedivy, Memory Speaks:
!['... The number of people they spoke their language with turned out to be even more important that [sic] the number of hours logged in that language.'](https://stancarey.files.wordpress.com/2010/05/julie-sedivy-memory-speaks-that-than.png?w=440&h=67)
William Gaunt, Turner:
!['From this time Turner was more nomadic that [sic] ever, while the accumulated canvases and drawings at Queen Anne Street began to moulder in neglect and decay.'](https://stancarey.files.wordpress.com/2010/05/william-gaunt-turner-that-than.jpg?w=442&h=61)
Joseph D. Pistone with Richard Woodley, Donnie Brasco: My Undercover Life in the Mafia:
!['...When Tony got lax and you got lax, you thought Sonny was more important that [sic] I am.'](https://stancarey.files.wordpress.com/2010/05/joseph-pistone-with-richard-woodley-donnie-brasco-that-than.jpg?w=442&h=109)
The Dispossessed by Ursula Le Guin:
!['The dinner cost a hundred units. Shevek ate very little of it, having eaten at noon, but he gave in to Vea's urging and drank two or three glasses of wine, which was pleasanter that [sic] he had expected it to be, and seemed to have no deleterious effect on his thinking.'](https://stancarey.files.wordpress.com/2010/05/ursula-le-guin-the-dispossessed-than-that-typo.jpg?w=442&h=96)
Stuart Sutherland, Irrationality:
!['...dismissal, particularly of senior staff, should be much more common that [sic] it at present is ...'](https://stancarey.files.wordpress.com/2010/05/stuart-sutherland-irrationality-that-that.jpg?w=442&h=117)
And on reputable websites such as BBC News:

The New York Review of Books:

The Irish Times:

Irish Times again:

The Guardian:

Time Out:

Wired:

TIME:

RTE:

An example from a linguistics paper on contrastive reduplication:

The Economist style guide’s Twitter account:

Subtitles in Andrzej Żuławski’s 1971 film The Third Part of the Night:
![Two young men in suits sit beside one another. The near man, in a dark suit, is shown in 1/4 profile. The other man, near the centre of the shot, is in a grey suit, almost faces the camera, and says: "The fate of non-existent people has never been more important that [sic] it is now."](https://stancarey.files.wordpress.com/2010/05/the-third-part-of-the-night-1971-that-than-typo-subtitles.png?w=450&h=284)
And in the 2019 Spanish film El Hoyo, aka The Platform:

![The same man at the sink continues, '...less fortunate that [sic] us this month.'](https://stancarey.files.wordpress.com/2010/05/platform-the-2019-that-than-typo-2.jpg?w=450&h=254)
The reverse typo than for that also occurs, as in this example from the Guardian:

And this one from Don Winslow’s novel Isle of Joy:

The Aspern Papers by Henry James, Penguin Popular Classics edition:
!["I hurried downstairs with her, and on the way she told me than [sic] an hour after I quitted them in the afternoon Miss Bordereau had had an attack of 'oppression,' a terrible difficulty in breathing."](https://stancarey.files.wordpress.com/2010/05/henry-james-aspern-papers-than-that-typo.jpg?w=440&h=88)