Measuring Death

You’d think the ultimate example of simplicity in measurement would be mortality rate.

dead guy
Dead guy

Count up the dead people  – they aren’t hard to catch. Divide by the total number of people you had when you started.

Done.

It’s not super complicated but it is slightly more complicated than that.

First of all, how do you figure the number of people in the population? The population changes all of the time. People are born, people die. So to compute annual mortality rate you use this formula

Total number of deaths from all causes in 1 year   X   1,000
Number of persons in the population at midyear

(You can also use per 10,000,  100,000  or million. There is nothing magic about the number 1,000).

You also may want to compute mortality for certain groups, for example, by age. You would then calculate the age-specific mortality rate  For example, if we want to know the mortality rate of children aged 15 and under it would be

Number of deaths from all causes in 1 year of children under 16  x  1,000
Number of children under 16 in the population at midyear

There is also cause-specific mortality rate

Number of deaths from specific disease in one year    x 1,000
Number of persons in the population at midyear

CASE-FATALITY is a very different thing than mortality rate. Case-fatality is

Number of individuals dying during a period after disease onset X 100
Number of individuals with the disease

For example, the annual mortality rate from measles in 1971-1975 was .17 per million

During that same period, the case fatality rate was about .1% or  .98 per 1,000.

Think about that. One person out of 1,000 who got measles died.

After a measles epidemic in 1989-91, increased vaccination rates resulted in a dramatic drop in measles mortality rates.

Unfortunately, measles are making a comeback in the United States due to stupid bastards who don’t vaccinate their children. Whether this will translate to an increase in mortality rate remains to be seen. With only 644 cases in 2014, there hasn’t been a reported death – yet.

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When not writing about death, I make educational adventure games where you can die if you get the math problem wrong. I’m a lot of fun.

Fish lake splash screen

Buy our games here for Mac or Windows.

local_offerevent_note January 27, 2015

account_box AnnMaria De Mars

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