"Comprise" is one of the most commonly misused terms in English. In this post, I will show you how to use it correctly and avoid the common pitfalls. The first main rule is that"is comprised of" is always incorrect. The correct phrases are actually either "is composed of" or just "comprise."
The second rule relates to the relationship between the nouns and "comprise." The first noun (the subject) refers to the group itself, whereas the other nouns (together, the object) refer to the individual parts of the group. To prevent confusion, always start larger and end smaller: "Group comprises parts."
The word "comprise" literally means "embrace"; metaphorically, this meaning is expanded to "include." When you consider this definition, you can see why "is composed of" is incorrect; it actually means "is included of"—a phrase that (I hope) sounds wrong to just about everyone's ears. The error only comes about because people are less familiar with "comprise" than they are with "include." As a shortcut, whenever you are using "comprise," try substituting "include" to ensure that it makes sense.
The common incorrect phrase "is comprised of" results from a blending of two correct terms with very similar meanings: "comprise" and "is composed of." Because "compose" and "comprise" look so similar, it is easy to swap them, thus creating the error. The words "compose" and "comprise" have opposite usages, though; "compose" means "make up" or "form," so "is composed of" means "is made up of" or "is formed from." This is similar to the meaning of "comprise" ("include").
Either "comprise" or "is composed of" can be correct in most cases. Just remember that forms of "comprise" are never followed by "of" (just as you'd never say "include of").
The second issue with "comprise" relates to the order of the nouns. Again, as with "include," the larger noun—the group—comes before the verb (as the subject), and the smaller nouns—the parts of the group—come after the verb (as the object). As above, simply try replacing "comprise" with "include" to see if the result makes sense. If not, you'll either need to swap the subject with the object or use another verb.
Let's consider some incorrect uses of "comprise"; we'll correct them in the next section. The key nouns are underlined, and the key verbs are in bold.
The Earth's landmass is comprised of seven continents and innumerable islands. Most full-length albums are comprised of ten to twelve tracks, but this one has thirty. Thirty-nine plays comprise the theatrical work of William Shakespeare. Two exams, three essays, and fifteen quizzes will comprise your final grade.
If you have written "of" after a form of "comprise," there are two fixes. First, you can use the equivalent form of the verb "compose":
The Earth's landmass is composed of seven continents and innumerable islands. Most full-length albums are composed of ten to twelve tracks, but this one has thirty.
Second, you can remove "of" and replace the entire verb (including any helper verbs, such as "is") with the appropriate form of "comprise":
The Earth's landmass comprises seven continents and innumerable islands. Most full-length albums comprise ten to twelve tracks, but this one has thirty.
Either fix should work in most sentences. I tend to prefer "comprise" to "is composed of" because the former is more concise, but if many people are more comfortable with "compose" than with "comprise"; if you are one of those people, know that "is composed of" works just fine. (Just don't say "is comprised of.")
Be sure to double-check to make sure that the nouns are in the correct order; the larger group should come before the verb, and the parts of the group should come after the verb. If the nouns are in the wrong order, there are two fixes. First, you can swap the nouns:
The theatrical work of William Shakespeare comprises thirty-nine plays. Your final grade will comprise two exams, three essays, and fifteen quizzes.
Note that the verbs stay the same in this fix.
Second, you can replace "comprise" with "constitute," as that has the opposite meaning and thus has its nouns in the opposite order. (With "constitute," the parts of the group are the subject, and the group itself is the object.) Here are the examples written with "constitute":
Thirty-nine plays constitute the theatrical work of William Shakespeare. Two exams, three essays, and fifteen quizzes will constitute your final grade.
Here, the nouns stay in the same order; you just replace the verb. Either fix works fine here as well; I will say, however, that you should choose the version that emphasizes the right nouns. Whichever noun comes first will have more emphasis. Thus, if you want to emphasize the group, "comprise" will be the better verb, but if you want to emphasize the individual parts, "constitute" will be better.
That's all for today! I hope you learned something about how to use "comprise" (and related verbs) correctly. I am always happy answer questions, so please leave a comment or email me (firstname.lastname@example.org) if you need help with a particular usage—or with anything else related to written English. Alternatively, you can just submit your documents for editing at ElevationEditing.com; I'll take great care of all your work—guaranteed.