Audience analysis is more often a process of guesswork than of an in-depth inquiry into the mind and activities of the user. In fact, it is pretty easy to analyze your audience without having to do any research.
Essentially, there are only two things that technical writers need ask themselves during the audience-analysis phase:
What does the user know about the thing I am writing about?
What does the user want to know about the thing I am writing about?
What the User Knows I think that, even if you were to analyze your audience for the next twenty-five years, you could not accurately figure out what the audience already knows.
So, how can you write stunning documentation when you don't know anything about the user? Basically, you can assume that some of your users are supreme experts in the technology, some of them are complete greenhorns, and everyone else falls somewhere in between. The trick is to write for the greenhorn without offending the expert.
You have all seen documents that use so many technical words and acronyms that your head aches after the first paragraph. Then there are the touchy-feely, namby-pamby documents that can make you feel sick to your stomach. "First we're going to put on the little bracelet, also known as a wrist-strap, which you will find attached to the unit." Neither of these documents has much respect for the audience. One offends the greenhorn, and the other offends both the greenhorn and the expert.
So, how can you write for the greenhorn without offending the expert? Well, I do this: I think of the user as someone who has a degree in every field except the one I am writing about. This way, I am able to tell the user everything about a product without showing off or being preachy.
What the User Wants to Know Most users want to know:
what the product does
how to install it
how to configure it
how to use it
how to respond to alarms and notifications
how to maintain the product
Of course, this list might not cover all of the information required by a particular project, but wherever you work as a technical writer, you will always have happy customers if you provide them with documents that contain the information listed above. Note that you do not have to provide users with relevant background information about your particular industry. For example, if you are writing the documentation for a product that is based on a Synchronous Optical Network, you do not have to tell users how SONET works.
Your documentation can be provided in a single book or in a series of books. Typical chapter/book titles are, in this order:
Configuration Guide or Provisioning Guide
User Guide or System Administration Guide
Alarms and Notifications or Alarm-Clearing Procedures
Routine Maintenance Procedures
Depending on the product, your user might also want the following documents:
Command Reference Guide
Site Preparation Guide
Emergency Recovery Procedures
In reality, audience analysis is a complex subject, which I have somewhat trivialized here. Even so, you can write excellent documentation even if you never have an opportunity to analyze your audience in any depth. Just assume that your users are knowledgeable about everything except the product you are writing about. Then tell them everything about it.