Imagine a tracking chip has been implanted inside your head without your knowledge. Everywhere you go, you leave an indelible, retrievable record of your whereabouts.

Now imagine placing your fingers on your keyboard and typing, "In my judgement, these findings are not surprising."

Ninety percent of your readers wouldn't notice the e after the g in judgement, but 10 percent would. They would notice you used the British spelling rather than the preferred American spelling: judgment.

So what? Who cares?

It depends on who's tracking your movements.

Most people wouldn't notice. Others might notice but wouldn't care. Still others would think it a harmless error.

But maybe 10% of your readers — among them careful writers, readers and editors — would think you careless.

It isn't that your error interferes with clarity. Your meaning is perfectly clear. But it suggests you haven't paid close attention to the finer points of spelling, grammar and punctuation or to the rules of language.

It also suggests you're likely to make similar errors. Worse yet, it suggests you may be careless in more substantive ways. Are your figures accurate? Can your details be trusted? Do you know what you're talking about?

Next you type, "My principle concern is that we operate in a competitive market, so I recommend we begin offering complementary checked baggage starting August 1st."

Now you're in real trouble, and not just with the nitpickers, who notice the nonstandard August 1st for August 1. (Curiously, dates are pronounced as ordinals but written as cardinals.)

Now you're in trouble with maybe a third of your readers, who know that principle can only be a noun, as in "She is a person of principle" or "There are five principles of good writing," and that principal, meaning "main" or "chief," can be either a noun or an adjective, as in "Our company has a new principal" and "The principal problem is sometimes credibility rather than clarity." If you use principle as an adjective, you're wrong.

The second major error in your sentence is the misspelling of complementary for complimentary. Complementary means "completes" or "goes with," as in "I hope our communication styles are complementary." Complimentary means "offered for free" or "offered as a courtesy." To praise someone, you compliment them with a compliment and a complimentary drink.

Still, none of these errors interferes with clarity and, so the argument goes, what does it matter if it's wrong as long as you understand what I mean?

Well, it doesn't matter — except to people who know better and who care, and that includes a good number of people who are in positions of authority and power.

Of course, some errors interfere with clarity. If you mistype a date, you may cause me to miss a meeting.

If you type, "Ask your team member, who submitted this report, to redo it," I think you have one person in mind. If you type the sentence without the nonrestrictive commas, you're identifying one person in a group.

To identify your own persistent errors, both harmless and damaging, google "Wilbers assessment."

Stephen Wilbers offers training seminars in effective business writing. E-mail him at wilbe004@umn.edu. His website is www.wilbers.com.