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The 7 plus or minus 2 rule

Image showing the numbers seven plus or minus two

Cognitive psychologists have suggested that short-term memory is able to recall between 5 (7 minus 2) and 9 (7 plus 2) chunks of information at any one time. This is occasionally called Miller's Law.

It is hotly contested whether that is really true. Research has certainly shown that this general rule varies depending on the nature of those chunks. However, I still find it to be a useful guideline.

For example, I usually consider the 7 plus or minus 2 rule when looking at the structure of the ideas I present in a document, presentation or pitchbook. I apply it to:

  • the way I structure diagrams,
  • the numbers of points I put in a bullet list,
  • the number of sub-headings in a section, etc.

Whenever I find the information chunked into fewer than 5 pieces, I ask myself whether it is worth trying to bring out more detail. And whenever I find the information chunked into more than 9 pieces, I ask myself whether it is worth trying to provide more structure.

By doing this, I hope that my material will be easier for the reader to absorb, digest and recall.

Examples to consider:

  • Next time you come across a "top 50 tips for..." article on the internet, ask yourself whether that list would have been more impactful had it been organised as 5-9 basic principles, each underpinned by 5-9 tips.
  • Or next time you look at a complex diagram, as yourself if it would have made more sense had it been organised into 5-9 groups of tightly bound interactions connected by more loosely coupled relationships.
  • Next time you look at the table of contents of a book or document, ask yourself if it is structured in the manner that best brings out the overall concept and structure of the work.

It is a guideline, rather than a rule. Just one more thing to think about. Often, I will look at something and conclude that it really is best presented as fewer than 5 or more than 9 chunks. But at least I will have thought about it and made a conscious choice.

Content should always be more important than presentation. But it is often presentation that makes the difference between content that hits its mark and content that misses it.


Anonymous said...

Vey insightful.

Anonymous said...