The Difference Between Causation and Correlation

One of the most common errors in the press is the confusion between correlation and causation in scientific and health-related studies.

In theory, these are easy to distinguish … an action or occurrence can CAUSE another (such as smoking causes lung cancer), or it can CORRELATE with another (such as smoking is correlated with alcoholism). If one action causes another, then they are most certainly correlated.

But just because two things occur together does not mean that one caused the other, even if it seems to make sense.

In general, we should all be wary of our own bias. We like explanations. The media often concludes a causal relationship among correlated observances when causality was not even considered by a research study itself. Without clear and definite reasons to accept that one thing CAUSES another, the fact that a correlation exists is all we should accept. Again, two events occurring in close proximity does not imply that one caused the other, even if it seems to makes perfect sense.

Once upon a time, this type of error wasn’t too bad.
If one ate a berry and got sick, it was wise to see meaning in that data. (Better safe than sorry). The same goes for a red-hot coal. Only one touch will give all the correlations needed. Being bullied by a primitive world of nature, it's far worse to miss a link than it is to make one up. A false negative yields the greatest risk.

Now conditions are reversed.
People in modern civilization are bullies over nature. New claims about causation are often made so we can make large interventions in nature. A false positive today often means approving drugs that have no effect, or imposing regulations that make no difference, or wasting money in schemes to limit unemployment. Now, as science grows more powerful and government more technocratic, the stakes of correlation…. of making counterfeit relationships and bogus findings,… grow larger and larger. A false positive is now more burdensome than it's ever been. The only thing we have to fight this attitude is the catchphrase. “correlation is not causation”.

I suggest that we be very cautious in the way we allow media claims to influence us into making personal changes in our own behaviors, ... especially in relation to the way they tend to limit our personal choices of the foods we eat, and the way they tend to add to our personal expense and health risks through recommendions of unnecessary drugs. 

Mistaking correlation for causation finds a cause that simply isn't there.