A statistician is teaching his class about the difference between correlation and causation. He uses many jargons, and class is completely lost in them. So he gives a simple example of causation, he says “contrary to ancient belief Sun doesn’t rise because cocks cry, but it is other way around. So the rising sun is the cause of cocks crying.” Then the topper of the class asks the example of correlation, to which the professor replies “Marks in examination and intelligence, could be correlated, but they may not necessarily cause one or other.” This line somehow offends the topper, he contradicts by saying “But I think our professors are intelligent enough to set a paper where marks are a true indicator of intelligence, so could the intelligence be not considered as the causation of marks.” The whole class covers their mouth for the muffled laugh.
The professor gets the sarcasm, and replies “you yourself based your premise on the intelligence of teacher not of the student, so the causation could not be direct. Further, if we go by your logic, Mosquito will be the most revered species, as wherever it goes, everyone starts clapping. So what caused what in that incidence.” All the class burst into laughter. But the topper stands still and says even in that incidence mosquito is causing the claps, it can’t be just correlation. The professor says “point taken, in this case, the mosquito is the cause of all the noise. Let me put another example. It will also tell us why the differentiation between correlation and causation is important.”
The professor starts with a story “many years back in the east Asian continent, there was a king who ruled the large kingdom. He cared for his people. One day a plague spread throughout his dynasty. He wants to do something for the people. He called people to give him ideas. One accountant of his royal court visited him, with few numbers. Accountant showed that in the provinces where maximum people are dying the number of doctors are also high. So the reference was doctors are the cause of all the deaths. King ordered to kill all the doctors.” The whole class sighed in sadness. Professor follows up with statement “Since correlation and causation were mixed up, the wrong decision was taken. It had caused not just many more people to die, but it eventually became the reason for the fall of that dynasty.” The class now understands the difference between causation and correlation, and the professor made sure that the class will not be forgetting this difference anytime soon.