Q. I’m reviewing a scientific manuscript in which the copyeditor has changed every instance of “using” to “by using”—for instance, “describe a vector by using Cartesian coordinates.” I can find no usage manual that comments on “using” versus “by using,” and other people’s opinions seem to be split. Does “using” require a “by”?
A. If “using” can be misread as “that/who is using,” then it’s a good idea to add “by”:
Describe a child using a pen.
Describe a child who is using a pen.
Describe a child by using a pen.
If the copyeditor doesn’t actually know whether a vector is able to “use” Cartesian coordinates, she might be hedging her bets by forcing you to approve her interpretation. If you think the copy is slightly clearer with the addition of “by,” consider keeping it. If it changes the meaning to something that isn’t correct, then reword your sentence so it’s clearer.