Miller's Magic Number

George Miller wrote a now famous paper in 1956:

The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information, George A. Miller (1956), Harvard University, First published in Psychological Review, 63, 81-97.

Technical writers, business writers, instructional designers and others have elevated the central concept to a truism of writing, which we call Miller's Magic Number. Basically, it goes like this:

• A list or sequence, to be retained easily in short-term memory, should contain no more than 7 +/- 2 items.

Some interpretation has been used to apply the number.

• A list or sequence could be a bulleted list or a numbered list.
• Corollary: Use subheadings to break long procedures into shorter sub-procedures (chunking).
• Use subheadings to break long bulleted lists into shorter, related lists.
• From Orr's Aphorisms: "Miller's Magic Number--no more than 7 +/- 2 items in a list--is not perfect all the time; but it's pretty good most of the time."

--David Orr