For many writers, a mixed approach works best, doing both simultaneously, or intermittently, carefully organizing an outline while stopping that to write down key ideas and ways of saying things so that they are not lost or left out because they don't fit one's initial outline. At some point in the process, though, some form of outlining is invaluable.

Correct outlining imposes organization on one's writing. The key organizational principle it imposes is that of a hierarchy of topics, ideas, or arguments. Finding that certain elements that cannot be entered into the outline compels the writer to face an important decision; either the element does not belong there at all, or the overall topic needs to be reconceptualized in order to encompass it. An element that is alone in its subordinate position, i.e. one that has no parallel element at its level beneath a given superordinate element, does not belong in that subordinate position but must be reconsidered instead as an inseparable part of the superordinate element. Outlining helps the writer follow a parallel structure in discussing successive topics, but does not require that where it is inappropriate. Simply put, outlining requires the writer to articulate the structure of his/her presentation.

This valuable tool is a means to an end, but if it becomes an end in itself the writing is likely to become mechanistic and boring. It can facilitate the development and presentation of ideas, but is not itself likely to be a source of ideas. This is probably why the mixed approach mentioned above seems to work best for the most successful writers.