Yes, it’s true: Fewer People Die in the Summer
Posted on June 23, 2011 by Stopher Bartol
I was recently asked to help settle a debate as to whether or not death is a seasonal event. In other words, is the mortality rate higher during some months of the year?
Sometimes I wonder…Why do I get asked this question? After all, Legacy.com is really more about life than it is about death. We help “bring obituaries to life” for our many newspaper partners and the funeral homes and families they serve; we help people remember; and we strive to make things just a bit easier for people at a very difficult time in their lives when they’ve experienced the loss of a friend or loved one.
In the process however, we do learn a lot about death trends and statistics, and I actually do know the answer to the question, so I will share it here for those who are interested.
Mr. Trollope was an Englishman writing in the 19th century, but his quote is relevant to modern day U.S. Indeed, there are seasonal fluctuations in U.S. deaths. One’s chances of dying in the winter months are significantly greater than in the summer. This is a statistical fact. It is generally true regardless of where one lives in the U.S., and it is borne out year after year.
Number of Monthly Deaths in the U.S. from Jan. 1985 – August 2008
Source: ICPSR, Inter-University Consortium for Political and Social Research
The chart shows how consistent this pattern is from 1985 – 2008. The blue line plots monthly deaths as measured by the y-axis, starting with about 200,000 in January 1985. They show an unbroken pattern of deaths peaking in the winter and bottoming in the summer. The green and red lines are simple and weighted averages that smooth out the lines to show the change in annual deaths over time.
From a rich assortment of government data, one can also build a predictive model showing relative daily deaths by month in the U.S. The following exhibit “indexes” daily deaths to equal “1” in January, which is the month in which daily death rates are the highest. The average daily deaths (the blue bar) for all other months are then shown as a fraction of 1. So for instance, in month 7, which is July, daily deaths are .8499 of January, or about 15% lower. The red and green bars represent a confidence interval, which in this case means the best prediction is the blue bar, but 90% of the time the actual number of deaths in a month will fall between the red and green bars.
Why is this important? Because those who serve the needs of people experiencing the death of a friend or loved one should be aware that their services will typically be in greater demand in December, January, and February than in June, July, and August, and they must be prepared accordingly. For example, if a newspaper picks one month to run public service announcements telling their readers about the obituary services they provide, they probably want that month to be sometime in late fall or winter when deaths are on their seasonal rise, so people will hear their message in advance of most needing to avail themselves of their services.