How’s the ranking worked out?
The world’s oldest ranking is quite difficult to precisely calculate as you can imagine. So we made a few assumptions and fudged it. If you’re really interested in how we did this here’s a bit from the technically minded people who wrote a very clever pseudo-scientific algorithm.
Finding a ‘near as possible’ ranking…
First we calculate your current age in years. This is easily done by subtracting your birth year from the current year, and subtracting one more if you have not had your birthday this year.
Then we take the worldwide age distribution for each five-year block of ages and pull out the numbers for the previous and next age, i.e. if you are 34 then we get the numbers for 30 and 35. The age distribution is taken from the US Census Bureau’s calculations as at 1 January 2009.
We interpolate the two numbers to find your current ranking. So the ranking at age 30 is 3,221,351,521 and at 35 it’s 2,722,716,568. If you are 34 precisely it’s 80% of the way from the first number to the second.
Catering for population growth…
Then we cater for population growth by taking the average daily birth rate and multiplying it by the number of days since 1 January 2009. There are about 75 million births per year so we divide that by 365 to get a daily rate. We count up to the second so we use a fraction of the current day as well. So if you visit the site twice in one day and enter the same information you will get slightly different numbers.
We multiply up the age-30 and age-35 numbers by their ratio to the total population. This means that the elderly fraction of the population goes up more slowly but the number of newborns goes up more quickly. This in turn means that as time passes, your ranking will decrease as your age increases. So if you visit the site on 1 May 2010 and put in your birth date, if you put in the same birth date on 2 May it will give you a lower number. But if you are a newborn on each day it will give you a higher number. Then we take that 80% fraction of the multiplied-up numbers to get your ranking today.
Getting as accurate as possible…
Lastly we add the ordinal values of any characters you enter in to the 'shoe size' box. Shoe size is a well known influencer of world age ranking.
Cutting to the chase…
If your age is over 110, we skip all of the above, and instead refer to the list of the world’s oldest people to tell you where you rank amongst them. You’re probably lying though, but just in case.