Correlation vs Causality – Differences and Examples


What is the difference between correlation and causality ?

Correlation Reports: The Solution for Large SEO Analysis

When running an SEO analysis for a high number of factors, the best approach to identify correlations between different factors is to user the correlation algorithm as Spearman, Kendall or Pearson. This allows us to understand if 2 different factors are changing on the same time in the same direction, and to estimate the influence level they might have on each other.

To understand how exactly the Spearman Correlation Algorithm works you shall check the next Youtube video:

What is the difference between Correlation vs Causality?

This might seem a simple question to answer. However, many people tend to mix up these two relationship,often causing incorrect conclusions .

Let’s see what each of the two terms mean :

Correlation – a relation between “phenomena or things or between mathematical or statistical variables which tend to vary, be associated, or occur together in a way not expected on the basis of chance alone”,according to Merriam-Webster

Correlation has a value between -1 and 1, where:

  • 1 would be a perfect correlation
  • 0 will be no correlation
  • -1 is a negative correlation defined as a relationship between two variables in which one variable increases as the other decreases, and vice versa.

Causality – the relation between something that happens and the thing that causes it . The first thing that happens is the cause and the second thing is the effect .

It is very important to know that correlation does not mean causality. While correlation is a mutual connection between two or more things, causality is the action of causing something .

For example, there is a correlation between ice cream sales and the temperature, as you can see in the chart below .

iceacream chart

As you can easily see, warmer weather leads to more sales and this means that there is a correlation between the two. However, we can’t say that ice cream sales cause hot weather (this would be a causation).

Same correlation can be found between Sunglasses and the Ice Cream Sales but again the cause for both is the outdoor temperature.

To understand better the difference between correlation and causality ,watch this movie .

This difference must be taken into consideration for SEO analysis when trying to identify the causality between different factors.