Scientific Illiteracy About Death Rates

 
Here's part of an article on ScienceDaily about death rates in New York City [New York City Death Rate Reaches Historic Low].

The death rate in New York City reached an all-time low in 2006, the Health Department reported today, as the number of deaths fell to 55,391 -- down from 57,068 in 2005 and 60,218 in 2001. Mortality declined in eight leading categories, including diabetes, HIV, chronic lung disease and kidney failure. The only leading killer that increased significantly was substance use (up 8%). Heart disease and cancer remained the city's biggest killers, claiming 21,844 lives and 13,116 lives, respectively. The figures come from the latest Annual Summary of Vital Statistics, the definitive registry of births and deaths in New York City.

The numbers of deaths are not death rates. This is one of my pet peeves. I get angry when newspaper reporters screw it up but this is much worse. It's from a website that's supposed to specialize in science ("Your Source for the Latest Research News").

The raw numbers are available at Summary of Vital Statistics 2006: The City of New York. They show that the death rate did, indeed, fall from 7.0 per 1000 citizens in 2004 to 6.7 per 1000 citizens in 2006. In 1916 it was 14.0 while in 1980, 1990, and 2000 it was 10.0, 10.1, and 7.6 respectively.

The absolute numbers of deaths tells you nothing about death rates. For all we know, the population of New York City could have fallen from 2004 to 2006 and the death rate could have gone up. (Incidentally, if you look at the raw data you'll see an interesting footnote. The rates in 2004-2006 were revised downwards when the 2007 census data for population was used. Previous estimates were based on the population according to the 2000 census.)

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[Image Credit: New York City in 1916 from The University of Texas at Austin]