The audience should know immediately what the document is about. The audience should have an idea why they are reading the document. To accommodate non-linear readers who may not read the whole document, the writer must indicate the most important findings of the document.
Headers increase the accessibility of a document.
Headers should use the same language as the overview sentence, and they should appear in the same order that they were mentioned in the overview sentence for greater accessibility. Give an example from the document where the writer makes the document most accessible. Give an example from the document where the writer makes the document the least accessible. Give an example from the document where the writer makes a general statement and supports it with specific details. Specificity increases a writer's credibility.