People who drown love ice cream O.O

In every statistics class I have ever taken I have heard the story of the correlation between amount of ice cream sold and deaths by drowning. Supposedly a study was done that found that both rates increase at the same time! Well we all know what that means... Ice cream must cause people to drown!

...or maybe people who drown love ice cream?

...or could there possibly be an unknown third variable!?

... or maybe, just maybe, it could have been by chance!?!

Who will ever be able to solve this problem!?!?

And that is where you find the downfall to comparative and correlation designs.

When comparing two variables, like ice cream and drowning, you may find that their rates both increase at the same time but maybe it is because there are other variables in play. (McMillan, 2012) In this case, it could be the fact that more people eat ice cream when its hot, which is also a great time for everyone to go swimming. Another example could be that, according to a study by Paul Kirschner, the more a person uses facebook the lower their GPA will be. (Kirschner & Karpinski, 2009) Other variables that may cause these to seem related could possibly be that a person who is on facebook all the time does not attribute enough time to studying, and then the lack of studying could relate to the lower GPA. So many other possibilities!

Another problem with correlation studies is that the direction is unknown. (McMillan, 2012) People who use facebook a lot may have lower GPA's because of it, or maybe people with low GPA's happen to really like facebook. One of the girls in the movie Mean Girls hit it spot on:

Ouch! 

Then there is the issue of maybe it is all just coincidence. (McMillan, 2012) What if there is no actual relationship other than the two variables are changing at the same time. What if kids who use facebook a lot just happen to have lower GPA's and there is no real relationship between the two. One could probably safely assume that the amount of ice cream sold does not affect how many people die by drowning. Unless ice cream makes you so dense that you cannot float, or it has some sort of magical quality to it that just makes your body incapable of floating. Those are bad thoughts though, because ice cream is too delicious to cause any harm other than a few extra pounds of fat........ which might even help you float O.O

I should stop there, and leave you with another nifty comic.

Just remember, Correlation does not equal causation!

McMillan, J.H. (2012). Educational research: Fundamentals for the consumer (6th ed.). Boston: Pearson.

Kirschner, P.A., & Karpinski, A.C. (2009). Facebook and academic performance. Retrieved from: http://lnx-hrl-075v.web.pwo.ou.nl/bitstream/1820/2880/1/Facebook_and_Academic%20Performance.pdf