Okay. After trying to put off blogging for as long as I could I’ve finally gathered the courage to at least ATTEMPT to write something understandable; statistics related and (hopefully) short. – I cannot guarantee that you will not die of boredom, sorry guys.
So, let’s start.
Correlation in psychological terms or scientific terms means that there is a relationship between two variables.
There are 2 types of relationships: positive (in which when one variable increases the other variable also increase) and negative (in which when one variable increases the other variable decreases).
An example of a positive correlation may be.. high sales of ice-cream is positively correlated with deaths by drowning.
And an example of negative correlation may be.. The older the person is negatively linked to donation making.
What is important to point out is that correlations are looking to see if there is a relationship. It’s an observation. A collection of data they haven’t manipulated. These variables are called co-variables.
Causation on the other hand is saying that one variable directly changed the other variable without the interference of extraneous variables. It’s saying that the Independent variable directly manipulated the Dependent variable. This isn’t just an observation anymore, it’s a manipulation that resulted in an effect.
So therefore, if a study published the findings that high sales of ice-cream positively correlated with death by drowning.. it does not mean high sales of ice-cream LED TO an increase in death by drowning or vice versa. All the correlation can tell us is that it COULD BE that one variable led to a change in the other variable or vice versa OR that the relationship is actually due to a third variable that effects the co-variables that were not accounted for (such as visits to the seaside during summer).
Okay so now that the difference is established. What does Correlation mean for Causation then?
Well, correlation can be quite useful. As a correlation is merely an observation of data to see if there is a relationship between two variables.. If a correlation is found this would give you a reason to see if the correlation found is in fact a causation!
So to conclude, correlation does not mean causation. It is a relationship. But it could be that the relationship COULD be due to causation. But in order to test that you would have to control third party variables.
I know this post has been boring. And I’ve overused the term variable way too much. But yeah, thanks for reading. And don’t shy away from buying and eating ice-cream during summer.
I promise to try and put more effort into my next blog post. =/