Fun Activity to Teach Correlation vs. Causation

One of the common arguments that anti-vaxxers use to support their cause is that as vaccination rates have increased so have autism diagnoses. People will even trot out pretty graphs showing a steep increase in autism rates following the introduction of the MMR vaccine. There is no medical evidence that vaccinations lead to autism as I discussed in a previous post. Making the leap from correlation to causation is fairly common, even among science majors, though. One of the first activities I do in my Neurophysiology class is a Correlation vs. Causation assignment (full activity: NeuroscienceSociety1_CorrelationVSCausation_2). I have students describe what conclusions they can draw from the graph below. I then have them design an experiment that would actually test whether organic food sales/consumption causes autism.

This activity is a good way to review things like independent and dependent variables, controlled experimental design, and to challenge them to come up with reasons why two things may be correlated. I also challenged the students to find news articles that improperly conflated correlation with causation and they came up with some doozies. For instance, people who have more sex make more money and kids who eat lots of candy are more likely to be jailed for violent offenses. No discussion of bad science would be complete without a mention of everyone’s favorite ‘Dr.’, Dr. Oz. He had a woman on his show claiming that carrying your cell phone in your bra could lead to breast cancer since she had developed a tumor at the exact location where she carried her cell phone. Some other fun correlations (that were reported as such) included decreased highway fatalities with increasing Mexican lemon imports and increased margarine in the house with increased divorce rates. My absolute favorite correlation (reported in a New England Journal of Medicine study with a proposed, although not directly tested mechanism) was that increasing chocolate consumption correlates with the number of Nobel Prize winners per capita. So, skip those late nights in the lab and eat more chocolate (or not if you learned something about correlation)!

5 thoughts on “Fun Activity to Teach Correlation vs. Causation

  1. Hope and Love

    You claim that autism caused organic food market to grow. Notice the lag/delay between the cause and effect.

    To explain autism, you need to look what happened BEFORE autism. It could be toxic food, isn’t it? Its exponential growth caused autism which in turn caused organic food market to grow.

    One could even go even further: autism is caused by something else which is very toxic and is administered more and more often. When the effect had been observed (the disease), then food was wrongly blamed, but caused organic food market to grow.

    It is quite simple to verify: find a control sample, i.e. which children did not get the disease (e.g. geographically). It could be isolated group of people, e.g. a religious group or residents of certain region. Check how often they get sick, what they eat, do they get vaccines.

  2. Interesting but when so many parents see their kids die or become autistic immediately after getting vaccines, the correlation becomes obvious. This is the first step in recognizing the need for doing a correlative analysis… that is, watching reality at work and then zooming in on the cause. In this case, we know that vaccines are the issue, Which ingredients, however, and what genetic make up? Remember that the VAERS numbers only represent 10% of all reported data, since doctors are trained that vaccines cannot harm, so they do not report vaccine damage and death into the system. I am a data scientist.

    • The person who did the autism – MMR vaccine study has been completely discredited. They even revoked his medical license. He had a massively flawed study and he was paid a huge amount of money by a person that wanted him to find a connection. EVERY legitimate study into the vaccine – autism link since then has not found a single connection between vaccines and autism. There is nothing there and yet people still believe that vaccines cause autism. This issue is an incredibly powerful example of the dangers of bad science. It also undermines people’s trust in the process and findings of science and , when that happens, you get our current climate where everyone just believes what they want to believe (i.e. our current CO-VID crisis).

  3. Wow! Thank you for so freely sharing your creativity and expertise! I am using this in my 9th grade Biology class in a discussion of sickle cell disease and the malaria parasite–much appreciated!
    Bev Marrs
    Albuquerque High School,
    Albuquerque, NM

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