Comprise vs. include

Guideline: Use comprise when you mean to “consist of” (as opposed to “are the elements of”). Use include when you are mentioning or listing some or most (rather than all) of the items in a series. Think twice before using is comprised of for anything.

1. The new water ski package comprises [consists of] a pair of Voit skis, a deluxe rope and handle, a ski vest, and (get this!) a shiny MasterCraft ProStar 190 ski boat.

or:

1. The new water ski package includes [has, in addition to other things,] a ski vest.

But not:

1. The new water ski package is comprised of [should be is composed of] a pair of Voit skis, a deluxe rope and handle, a ski vest, and (get this!) a shiny MasterCraft ProStar 190 ski boat.

A closer look: Is comprised of has become so commonly used as a synonym for “consists of” that many [inferior] guides now consider the phrase standard.

Source: Grammar for Smart People by Barry Tarshis.