Correlation/Causality Confusion

As the social media space slowly matures, we’re starting to see more and more reports released by companies offering insight into the ebbs and flows of peoples’ behaviour online. Not surprisingly, these reports are pretty popular – they possess two desirable attributes:

  • They offer easy-to-digest, soundbite-sized nuggets of information – perfect for short-form media such as Twitter
  • They offer the potential for increased understanding of the latest trends

However, these reports can sometimes unintentionally misrepresent the data, through a simple statistical error:

Correlation does not dictate causality.

What does this mean?

It means that just because there is a link between two things, it does not mean that one causes the other. So, if there is a correlation between A and B:

  • A could cause B
  • B could cause A
  • C (and/or D, E, F etc) could affect both A and B

As Bob Hoffman explains it over at The Ad Contrarian:

If you were to study people who are hard-of-hearing you would probably also find that they have a much higher likelihood of being bald. Does this mean that bad hearing causes baldness? Of course not. It occurs because old age causes both hearing and hair loss. So there is a correlation between deafness and baldness, but there is nocausality. One does not cause the other.

One more time: correlation does not mean causality. Just a quick thought, but an important one. Remember this next time you read a snippet about a new study, and make sure you always read closer before believing the headlines.

(Image: Shutterstock)

Dave Fleet
Managing Director and Head of Global Digital Crisis at Edelman. Husband and dad of two. Cycling nut; bookworm; videogamer; Britnadian. Opinions are mine, not my employer's.