People, as receivers, as an audience, seek benefits when they read, watch, or listen.

Persuasion is the most obvious transaction between benefit-promisers and benefit-seekers,

Expressive works (in books or movies) give us many benefits and pleasures: empathy, understanding ourselves and others, escape, diversion, curiosity, and enjoyment.

Exposition provides us information as its primary benefit.

Information is the means by which we gain specific immediate benefits (e.g. directions, instructions, warnings) or general future benefits (general knowledge and understanding, historical perspective). We commonly assume that it is better to be informed than to be ignorant, that "knowledge is power."

As an expository writer, your role is to provide your audience with good, accurate, clear, coherent, and useful information.

If you give your audience inaccurate information, erroneous data, or wrong directions, you err. So also, you err if you are wordy, clumsy, or repetitive.

Information may be accurate, but, if it is not presented coherently, then it's useless. Consider an unsorted box of computer print-outs which may contain accurate data, but are of little use to anyone.

As a writer, your job is to compose - to put together - clearly and coherently so your target audience can use it easily and benefit from it.

In classroom situations, your instructor often becomes a "captive audience" who has to read what you write.

However, in most situations, if you don't write well, or if you don't provide the expected benefits, your audience doesn't have to read your writing. They will find someone else who can do the job better.

Even though expository writing is primarily topic-centered (and doesn't have the obsessive concern with audience response that persuasion needs), it is still designed to be read by another person. Ask yourself: What benefit is your reader seeking ?