Correlation vs Causation in Data Science

A short and sweet explanation using real-world examples.

Sundas Khalid

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Let’s jump into it right away.

Correlation

Correlation means relationship and association to another variable. For example, a movement in one variable associates with the movement in another variable. For example, ice-cream sales go up as the weather turns hot.

A positive correlation means, the movement is in the same direction (left plot); negative correlation means that variables move in opposite direction (middle plot). The farther right plot is when there no correlation between the variables.

Causation

Causation means that one variable causes another to change, which means one variable is dependent on the other. It is also called cause and effect. One example would be as weather gets hot, people experience more sunburns. In this case, the weather caused an effect which is sunburn.

Photo by Anthony Figueroa correlation is not causation

Correlation vs Causation Difference

Let’s try another example with this visualization. Your computer running out of battery causes it to shut down. It also causes video player to shut down. Now, computer and video player shutting down events are correlated; the actual cause is running out of battery.

Photo by Lionel Valdellon correlation vs causation

Why is this important in data science?

How many times have you seen studies that imply A causes B. For example, going to the gym results in higher productivity and focus. Is this really causation?

As a data scientist, you should not let the correlation force your into bias because it can lead to faulty feature engineering and incorrect conclusions.

Correlation does not imply causation.

If you were to write a machine learning model for gym and productivity relationship, instead of focusing on features that are correlated (going to gym), you should focus on actual causes of high performance (hard work, perseverance, routine, etc) to…

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Sundas Khalid

I write about data science, diversity & lifestyle | currently at Google | more learning content at sundaskhalid.com