In Modern Feature Writing (1949), DeWitt Reddick offered five rules why outlining the article is important:
1. A good outline insures logical development of thought. The outline permits the writer to view the structure of the whole before he begins writing. By looking at this skeleton he can make sure that each major idea has a proper relationship to the central theme.
2. A good outline helps to secure unity. For every article the writer should gather more information than he uses. It is important that he see clearly what to leave out as well as what to include. The outline aids in proper selection of material.
3. A good outline aids in securing proper emphasis on the various elements. After the author has selected his material, he still faces the task of deciding the emphasis to be placed on each of the items or groups of facts. An outline clarifies the main points to be introduced as topic sentences and indicates the material to be subordinated.
4. Careful preparation of an outline permits the writer to consider in advance the style to be used in developing each important section.
One idea in the article, perhaps, can be presented most clearly by a narrative incident; another is complex and needs clarification by means of a hypothetical situation; a direct quotation from an authority will give greatest force to another important thought.
As he prepares his outline, the writer can decide upon the literary devices for the effective presentation of each idea.
5. An outline aids spontaneity in writing. The preparation of an outline exercises the mind of the writer, steeps it in the material, and creates the mood of the article.
Thus, when he begins to write, he will have less trouble overcoming initial inertia and will be able to move along more swiftly because he knows in advance how he will approach each section.