OK, everybody, repeat after me: The whole comprises its parts. Bear this in mind as you read further.
The parts do not comprise the whole, nor is the whole comprised of the parts.
But the whole may be composed of—and even consist of or be made up of—the parts.
If this confuses you, take heart. Comprise looks a lot like compose and consist, but it doesn’t behave in the same way. And that explains why it is commonly misused.
Take a look at this string of examples:
The board of directors comprises 12 members.
That is, the whole (board) comprises the parts (members).
You could also say:
The board of directors is composed of 12 members. Or:
The board of directors is made up of 12 members. Or:
The board of directors consists of 12 members.
Swinging the sentence around, it’s correct to say:
Twelve members compose the board of directors. Or:
Twelve members make up the board of directors.
But you could not say:
Twelve members comprise the board of directors. Nor could you write:
The board of directors is comprised of 12 members.
That’s because the whole comprises its parts—and not the other way around.
Comprise is interchangeable with is made up of—not make up. To see how this works, consider this example:
The board of directors makes up 12 members.
Not only is the statement not valid, it does not make sense.
The easiest way to keep this straight is to remember this simple rule: Avoid using is comprised of at all costs. It has no place in the English language. Use comprise—but only when you’re communicating about the whole.