Prof. George Klare, an expert on the readability of texts, uses a visual angle to demonstrate the reader's behaviour. His model of reader performance explains how readers will read better if you keep certain things in mind.
Model of Reader Performance. Adapted from Klare (1980).
Rule 8: Your readers will read better if you cater for their competency, motivate them to read on, give them the content they want, and pitch your writing at the correct readability level for that reader.
First of all, the reader will read better if you write according to how competent he or she is. That means you need to ask yourself what your intended reader's literacy level and technical knowledge of the subject are likely to be. When writing for an auditor, for instance, you can pitch your style at a high technical level. When writing for a media publication whose reader audience varies greatly, steer clear of the technical jargon and keep it as simple as possible.
Reader motivation centres around dangling that hook (the subject of blog post 2). What would catch your reader's attention and then keep him or her reading?
As regards content of material, think back to WIIFM, discussed in blog post 3.
An auditor would be concerned about sufficient documentation and compliance with GAAP, for instance.
Her client, on the other hand, would care more for cost flexibility and earnings per share.
Readability has to do with your writing style. We'll be giving lots of attention to that later on. In short, though, it's about writing in such a way that it's easy for your reader to get what you're saying.
To sum up: Write for your readers' competency, motivate them to keep reading, give them relevant content, and get the readability level right.