Difference Between Correlation and Causation

Correlation vs Causation

We often hear words like correlation and causation, especially, while dealing with research papers, also when studying different natural phenomenon. These concepts are also heavily used when trying to establish link or direct association between two events. There are some who think correlation and causation are synonymous or at least similar. However, there are differences that cannot be ignored and are being highlighted in this article.

Take a look at this statement “Lung cancer is caused by smoking.”

This statement assumes that smoking is the only cause of lung cancer, and tries to establish a causal relationship between smoking and lung cancer. However, there is no definitive proof that cigarette smoking person will eventually have lung cancer, as there are genetic differences between people and they also have different immunity levels. Thus, it is better to say that though there is a definite correlation between lung cancer and smoking, it is inconclusive that smoking does cause lung cancer. This also establishes a strong point that correlation whether weak or strong does not mean causal relationship.

Now take a look at this statement “Sound is heard a little later whenever there is lightening.”

We all know that there are both sound and light associated with lightening, and it is always lightening that is seen first and sound is heard a little later because of the difference between speeds of light and sound. This is a causal relationship, so we hear lightening sound whenever the phenomenon of lightening takes place.

There is improvement seen in the grades of students who spent more time on studies at home. Does this mean there is a causal relationship? May be, but it cannot be said with certainty. Is there any association of increase in intake of junk food and obesity? Yes, certainly as it can be proved using a group of people and by increasing their intake of junk food.

If one variable is causing a change in another, the relationship between the variables is one that is causal. On the other hand, one event takes place often in the presence of another means, they are correlated, though it is difficult to say there is a causal relationship. It is easy to say that the lung cancer in a person is caused by his habit of smoking though, it may be just one of the causal factors.

It is seen that eating breakfast early and then going to school is associated with good grades in school. However, to jump the gun and say that there is a causal relationship between early breakfast and good grades would be not only illogical, it would also be totally erroneous. It so happens, that those who come without having breakfast appear to be tardy and dull. Perhaps this is what makes teachers compare the two groups of students establishing a causal relationship between breakfast and good grades.

It is very difficult to establish a causal relationship between two variables, and only when one is absolutely certain about the relationship, that a causal relationship can be established.