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Since spelling and grammar checkers don't test consistency, documents can seem to be error-free and yet still contain lots of mistakes. Consistency mistakes are notoriously difficult for authors to spot, but they jump out at readers and cast doubt on the author's ability.

What is a Consistency Mistake?

Consistency mistakes come in many forms. This article looks at only spelling and hyphenation consistency. For example:

  • The word 'colour' shouldn't usually appear in the same document as 'color'
  • 'organization' shouldn't be with 'organisation'
  • 'e-mail' shouldn't be with 'email'
  • 'door-to-door' shouldn't be with 'door to door'
  • the prefix 'anti' shouldn't appear with a hyphen in one place but without a hyphen in another
  • numbers and fractions shouldn't be spelled with hyphens in one place but without them in others.

There are exceptions. Hyphens depend on context and spelling differences may occur within reference lists or quotes. However, these are often mistakes and need to be checked.

A Shockingly Frequent Mistake

Most people think they write consistently. However, the facts prove otherwise. We used PerfectIt, Intelligent Editing's add-in for MS Word, to test over 3000 documents (randomly selected with the Google search term 'final report') to determine the frequency of these errors. The results are staggering. The chart below shows the number of consistency errors we found in each document.

Spelling and hyphenation errors The number of spelling and hyphenation errors per document by document size (Enlarge image)

The results show that for documents between:

  • 1000 and 2000 words, around half contain a spelling or hyphenation inconsistency
  • 2000 and 3500 words, the proportion is around three quarters
  • 3500 and 10,000 words, just one in 10 documents showed no consistency mistakes.

Of the 186 documents we tested that were over 10,000 words, every single one had at least one consistency issue. Since some inconsistencies are intentional (and correct), these are not all necessarily mistakes. However, the proportion with many consistency issues is alarming and suggests there are a lot of errors. We found that one in four documents over 1500 words contain five or more hyphenation/spelling inconsistencies. In documents over 10,000 words, that ratio rose to 94%.

Easy to correct… and free!

Though difficult for authors to spot, these mistakes are actually easy to catch with a computer. Launched in July 2011, Intelligent Editing's online consistency checker is free to use and provides a report that lists every hyphenation and spelling inconsistency in your document. To try it:

The checking is automated, secure and takes just a minute or two to complete. It works with DOC, DOCX, PDF and TXT files, and it can be accessed from any computer. Try the online consistency checker now.