April 24 – Happy Birthday, John Graunt

Posted on April 24, 2014

At the time that Graunt lived,
the European fashion for
hats was the capotain, seen
here. Both men and women
wore capotain hats.
Today's birthday boy made and sold hats—in other words, he was a haberdasher.

I am not writing about him because of his haberdashery, though. As a matter of fact, if ALL he ever did was make and sell hats, I never would have heard of John Graunt. He did, after all, live about 400 years ago!

No, the reason I am writing about Graunt—the reason he is famous—is that he was one of the world's first demographers.

Demography is the study of human populations through statistics, such as numbers of births, deaths, and marriages, amount of income, and so on. Graunt, born on this date in 1620, was able to use more than a century's worth of records of baptisms and deaths, kept in English churches, to answer questions about death rates. He discovered that death rates differed for men and women, and that death rates differed for city and rural populations.

Because he looked at the causes of death, Graunt is also considered one of the first experts on epidemiology (the study of the spread of diseases). He even tried to help England's king create a system of warning of the onset and spread of bubonic plague, using statistics; even though the system never was completed, Graunt's efforts did create the first statistically based estimation of the population of London.

Graunt presented his demographic studies to the Royal Society. Apparently many members of the Royal Society wanted nothing to do with Graunt and did not want a mere haberdasher to be elected to their august organization. But Charles II, King of England, brought Graunt into the society despite their reluctance.

Unfortunately, Graunt lived at a time when religious differences were tearing apart the nation; Graunt had converted to Catholicism shortly before the Great Fire of London, and when the fire was blamed on Catholics, Graunt lost his job. He ended his life very poor, suffering from some of the diseases he may have studied.

Explore demography

In the almost four centuries since Graunt, improvements in medicine and hygiene have improved our lives and health. However, all is not equal all over the world. Check out this graph of life expectancy (above), which shows that women tend to outlive men and the not-at-all-surprising fact that people in richer nations tend to outlive people in poorer nations. The Wikipedia article that provides the graph also gives the rankings and the hard numbers. Try to guess where your own nation will appear in the chart (#1? #7?) before you check it out. 

ChartsBin has a map that shows the daily calorie intake per capita (per person), all over the world. 

Demographic studies often tell us sad truths. I looked at this bar graph (below) showing the income gap by race in my own nation, the United States. I hoped that the fact that the numbers were from ten years ago would mean that the gap had shrunk...

...but then I spotted this graph (below) of the income gap by race and gender, and I realized that the gap has probably grown. This graph shows growth in the income gap along racial and gender lines for the last forty years of the last fifty years, and I fear that the trend has continued! Can you discover whether or not the gap has widened even more from 2004 to 2014?
The dates along the bottom of the graph range from '68 (1968) to '08 (2008),
with each number being two years beyond the last.

The average annual income is shown by the horizontal bars, with $10K
being the bottommost line, then $20K, $30K, $40K, $50K, and the
top line being $60K.
In other words, each horizontal line is separated from the one
below by ten thousand dollars.


Also on this date:


First Day of Summer in Iceland









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