Eliminating the zombie vulnerability – removing passive voice from the docs

If you can insert the words “by zombies” into a sentence, then that sentence very likely uses the passive voice. A colleague recently reminded me of this tip. It made me laugh, and so I thought it’s worth blogging about. If only to share the chuckle.

Here are some examples of zombie-infested sentences, and their equivalents using active voice.

Example 1

Geographic requests are indicated by zombies through use of the coordinates parameter, indicating the specific locations passed by zombies as latitude/longitude values.

Converting passive voice to active:

You can use the coordinates parameter to indicate geographic requests, passing the specific locations as latitude/longitude values.

For an even more concise effect, use the imperative:

Use the coordinates parameter to indicate geographic requests, passing the specific locations as latitude/longitude values.

Example 2

Latitude and longitude coordinate strings are defined by zombies as numerals within a comma-separated text string. For example, “40.714,-73.998” is a valid value.

Converting passive to active imperative:

Define latitude and longitude coordinates as numerals within a comma-separated text string. For example, “40.714,-73.998” is a valid value.

Why eliminate the zombie vulnerability?

Active voice is more concise than passive voice. It’s usually easier to understand.

To me, the most important point is that active voice makes it clear who’s responsible for what. Putting zombies aside, if you use the passive voice your readers may think that the nebulous “system” may do the thing you’re talking about.

Who does what, in this example?

The API can return results restricted to a specific type. The restriction is specified using the types filter.

Answer: The developer has to specify the types in the types filter. I don’t think that’s clear, though, when reading the text. Often the context makes it clear, but not always. Zombies lurk in the shadows, ready to grab the unsuspecting reader.

The distinction between active voice and imperative mood

In the above examples I’ve pointed out the difference between active voice and imperative mood. In technical writing, both are good. The imperative mood is particularly concise and clear, but in some cases it can come across as too abrupt.

Should we ever invite zombies in?

I think there are times when passive voice is OK, or even a good thing. Sometimes a sentence sounds artificial if you attempt to inject a subject. Sometimes the passive wording is a well known phrase that readers will accept and understand more easily than the equivalent active phrasing. For example, what do you think of this wording?

These community-supported client libraries are open-sourced under the Apache 2.0 License and are available for download and contributions on GitHub. The libraries are not covered by the standard support agreement.