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)!

Talk to Your Friends and Family About Science: Ebola in the US

Somewhat inevitably with the global nature of travel these days, the first Ebola case in the US has been reported in Dallas. While this is obviously scary for the patient and his family, there is almost zero chance this will lead to a widespread outbreak in the US. Below are a few things to remember about Ebola.

Only people showing symptoms are contagious

Although the Ebola patient did travel on an airplane, he was not showing symptoms at that time and therefore was not contagious. The public health team in Dallas has traced his contacts since arriving in the US and will be monitoring those people to ensure they do not develop Ebola (Ebola has a 21 day incubation period).

Ebola is only transmitted through infected bodily fluids

Ebola is actually relatively hard to get. Ebola is not spread via airborne droplets and there is no reason to believe airborne transmission of Ebola will develop. Like with HIV, you must come in contact with bodily fluids from a person showing symptoms to contract Ebola. Just being in the same room with the person will not lead to Ebola spread.

The US Public Health infrastructure is equipped to deal with Ebola

Unlike in West Africa, the US has a robust public health system, well trained medical professionals in every community, and no shortage of the personal protective equipment necessary to prevent the spread of Ebola. In fact, Ebola related viruses like Marburg and Lassa Fever, have already made it to the US and no widespread outbreak occurred.

We should be more worried about the effect of the Ebola outbreak in West Africa

While we really shouldn’t be worried about a US Ebola outbreak, we should be more worried about the havoc occurring in West Africa. The outbreak is causing a tremendous amount of suffering in West Africa. The public health system is completely overwhelmed and non-Ebola medical care is suffering as well. There are extreme shortages of trained medical professionals, personal protective equipment, beds for those suffering from Ebola, and other basic medical supplies.

If you are worried about Ebola, consider donating to Doctors Without Borders to help fight the spread of Ebola in West Africa. Aid groups on the ground, like Doctors Without Borders, are also asking for help from any trained medical professionals willing to volunteer in West Africa.

A Few Other Resources About Ebola in the US:

CDC Ebola Information Website and Press Release

Tara C. Smith’s article in the Guardian about why we shouldn’t panic about a US Ebola Epidemic