When a writer asked me to rank what I looked for when I edited, I gave this answer: accuracy, clarity, readability, and correctness.

An accurate document that is unclear, difficult to read, and grammatically incorrect is worth more than an inaccurate one that is clear, easy to read, and grammatically correct. The accurate document with the faults I described will result in confusion, wasted time, and perhaps even anger from the chief executive officer through the staff to the worker on the production line. But if the company makes, say, tennis balls, eventually they will be sailing across nets and bouncing predictably. Not so with the inaccurate document. These balls will likely be square and never see the grass at Wimbledon.

I sometimes, but not often, find inaccuracy in documents, in part because the fine engineers, soldiers, analysts, scientists, and programmers I work with are very meticulous writers. Finding something inaccurate in a document, a data requirement that will not satisfy a criterion or an open parenthesis in a formula, means to me that the writer is overworked.

Clarity and readability do not have the same meaning, but they are closely related. They rely on many of the same rules. A clear document, however, means that we cannot possibly misunderstand it. A readable document means we waste no time doing so. A 60-word sentence may be clear, but if the writing, not the content, forces us to read it several times, then the sentence isn't as readable as it should be.

Editors earn most of their pay by helping writers make their documents clear and readable.

Correctness refers to the rules of grammar, mechanics, and punctuation. Are these important? Yes, for two reasons. Sometimes even a comma can change the meaning, and thus correctness can affect accuracy. Far more common is the impression incorrectness gives readers. When we write with poor grammar, mechanics, and punctuation, no matter how accurate, clear, and readable our prose, readers disrespect us and distrust our writing.