Consumer Psychology

Correlation vs Causation

Dominoes in B&W (B1938)

Image Credit: Sue F

Correlation vs Causation

Anyone who has been exposed to a psychology or statistics class knows the idiom “correlation does not equal causation.”

Logic nerds know this phenomena as the Latin “Post hoc ergo propter hoc”  or to the rest of us “after this, therefore because of this”. This is a flaw in human psychology that happens when we see one event correlate with another we think that they must have some causal relationship.

NOT TRUE (not always anyway)

The small scale example of exploiting this flawed thinking is;

The rooster crows immediately before sunrise, therefore the rooster causes the sun to rise.

The fallacy lies in coming to a conclusion based solely on the order of events, rather than taking into account other factors that might rule out the connection. Post hoc ergo propter hoc focuses on the sequence of events and everyone can see the flaw in this logic.

What about more complex correlations? Correlations where we can see over vast amounts of time the 2 variables are so closely linked that you’d be crazy not to make the connection. Down the rabbit hole we go with

Tyler Vigen—or more accurately, Tyler Vigen’s software takes correlations in public data sets and pumps out ugly but awesome graphs in response.


Who knew that the number of people who drowned by falling into a swimming-pool correlates with the number of films Nicolas Cage appeared in?




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