No one doubts that indexes are of value to readers. But they can also be of value to their own authors as editing tools. Because an index provides a microcosm of the main text, errors in that text will often be reflected in the index, and reflected in a way that makes them more visible. As he creates the index, the author can use it to spot errors in the body of the work—errors of terminology, of arrangement, of proportion, and of omission. This technique can be used to supplement the normal editing process.

The problems with flawed technical documents are frequently problems of a larger nature. When the subject to be described is itself amorphous or internally illogical, technical writing may only dutifully reproduce the inherent confusion. Writers should be alert to identifying these problems and assisting product/procedure designers in eliminating confusion at its source.