1950: Chicken Pox and Name Statistics
In this comic statistics are used to point out some non-intuitive correlations. The first panel sketches out the prevalence of chicken pox by age in the United States.
As the graph indicates, prior to the introduction of the varicella vaccine in the United States, it was an exceptionally common childhood illness, with almost 100% of the population experiencing it at some point. The illness is highly memorable (since the symptoms last for days and are intensely uncomfortable) and noticeable (since the characteristic blisters are distinctive and difficult to hide), meaning that it was once a common experience that people expected to both experience and see in their peers.
As the vaccine became widespread in the US, rates of varicella infection declined dramatically, and new infections are now relatively uncommon. The graph points out that this has led to a fundamental shift in experiences by age. For an American over the age of 30, nearly all your peers growing up would have had chicken pox. For an American under the age of 10, virtually none of them would have had it. This means that older people are likely to think of chicken pox as a normal part of life, while children are likely to have no experience with it, and may not even know what it is.
The second, seemingly unrelated graph, charts the popularity of certain names over time, in the US. It's normal and expected for certain names to rise and fall in popularity over time, which means that the number of people with those names ends up clustered by age. The names "Sarah" and "Brian" have gone from being highly popular to relatively uncommon for new babies, meaning that people with those names are much likelier to be older. Names like "Logan", "Brooklyn", "Jaxon" and "Harper" went from being virtually unused to having a spurt of popularity, meaning that (as of 2018) people with those names are much more likely to be under the age of 15 than over it.
The final panel points out that these trends, taken together, generate the interesting effect that you can, in some cases, estimate the odds of someone having had chicken pox, based solely on their first name. Having a name like "Brian" or "Sarah" raises the odds that you're over 30, which raises the odds that you had chicken pox. People named "Harper" or "Jaxon" are almost certainly young enough to have grown up with the vaccine in broad use. These time-based trends predict both the odds of a person having had the illness personally, and the odds that they grew up in a time when infections were common and generally expected.
The cartoon demonstrates the correlative fallacy, i.e. what can go wrong if one attempts to draw conclusions based on a random comparison of two variables, as described by the famous saying: "". In this case, there's a real correlation between names and the incidence of a particular disease. A superficial reading could suggest that either certain names make people prone to the disease, or that the disease, in some way, impacts a person's name. The real cause of this correlation is simply that certain trends just happen to coincide, causing them to statistically correlate without either variable having a real causal affect on the other.
The citations are real articles. The first citation DOI:10.15585/mmwr.mm6534a4 is on the Center for Disease Control (CDC) web site at  and the second citation DOI:10.1016/j.vaccine.2012.05.050 is an article in Vaccine at . Both articles describe the effects of the vaccine for varicella which is the virus that causes chicken pox and shingles (also known as herpes zoster).
The title text states that people with all six of the names in the last panel (and indeed, most people in general) tend to think that it's weird we have teeth after thinking about it for a while, but that people named Trevor don't in an unexplained statistical anomaly. Teeth are a normal and near-universal part of the human anatomy (and that of many other animals). Like many aspects of biology, they're generally taken for granted, but can seem "weird" if you think about them too much. Randall has often demonstrated a tendency to over-analyze typical aspects of life until they become troubling. Here, he jokes that people with one particular name (Trevor) don't experience this, for unexplained statistical reasons. This is, of course, fictional. The joke comes from the fact that, were that claim true, it would be as random and as hard to believe as the real phenomenon that the comic addresses.
- [The first panel shows graph with only the x-axis labeled and with seven labeled ticks. The y-axis has three ticks with percentage labels. A red line rises from bottom to top as it goes from left to right. There is an arrow pointing at the graph with a label. Above the left part of the red line there is a title and beneath that a reference to the source of the data in gray font.]
- [According to the graph, the percentage is close to 0 for ages below 15 and close to 100 for ages above 30.]
- Fraction of kids your age who got chicken pox
- (Very rough US estimates based on DOI:10.15585/mmwr.mm6534a4 and DOI:10.1016/j.vaccine.2012.05.050)
- Your age: 5 10 15 20 25 30 35
- Vaccine introduced in 1995
- [The second panel shows a graph with only the x-axis labeled and with seven labeled ticks. The graph has six gray lines with labels on them. To the right is a title and beneath that a reference to the source of the data in gray font.]
- [According to the graphs, Sarah and Brian are more popular names for older age groups.]
- Relative popularity of several names in your age group
- (Source: ssa.gov)
- Your age: 5 10 15 20 25 30 35
- [The third panel shows a list of names with a percentage next to them. Above the list is a title and beneath that a statement in gray font:]
- Chicken pox incidence by name:
- (Very rough estimate)
- Brian: 75%
- Sarah: 60%
- Logan: 20%
- Brooklyn: 10%
- Jaxon: 4%
- Harper: 2%
- [Caption below the panels:]
- Fun Fact: People named "Sarah" and "Brian" think chicken pox is normal and common, and people named "Logan" and "Harper" do not.
- This was the first Fun fact comic in more than two years, to be followed just three weeks later by another Fun fact in 1959: The Simpsons.
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