On readability

The bottom line on any technical document is whether the user can read, understand and successfully apply the instructions.

So how important is readability?

Think of it this way. You have a Ferrari parked in your driveway—a vibrant red package of elegant engineering, speed and sex. This is the car you’ve wanted all your life. You can already feel the pressure of the acceleration pushing you into the driver’s seat, you can hear the wind beating against the windshield… but the dealer just told you the factory didn’t include a key with the car. Did you just spend a quarter mil for something you can’t use?

Readability is the key that turns on the value in your technical manuals, guides or any other user instruction.

The Flesch-Kincaid readability tests were originally developed for the U.S. military for use in assessing the accessibility of technical manuals. Could the guys in the classroom assimilate the data fast enough to get the technology viable? Could the grunt in the field follow the instructions without the aid of an instructor? These tests are based on mathematical analyses of a document’s content.

In the Flesch Reading Ease test, a higher score indicates easier readability.

For the Flesch-Kincaid Grade Level test, the analysis gives a grade level. The higher the grade, the harder the read.

Just for fun, we took a legacy manual from one of our clients and ran it through these tests. We then did a first draft rewrite and ran it through again. The results were interesting:

…And this was only first pass!

One of the things FK tests for is use of passive language. For example, “The button is pressed…” (passive) versus “Press the button…” (active). Active voice spurs the reader to do something, while passive voice tends to make the data sound less important.

If you expect the user to do something, use the active voice.

These FK tests address only one aspect of readability—language. The are other factors that contribute to a technical manual’s usefulness, including font style and size, column width, and use of white space.

Another factor that can dramatically improve the user’s understanding is technical illustration.

At Precision Wordage, we take all of this, and more, into account when developing any kind of user instruction, because the bottom line on any technical document is whether the user can read, understand and successfully apply the instructions.

– Su