Serial numbers...

[Lasse Langwadt Christensen]

torsdag den 4. maj 2023 kl. 01.46.10 UTC+2 skrev Don Y:

On 5/3/2023 4:13 PM, Lasse Langwadt Christensen wrote:
torsdag den 4. maj 2023 kl. 00.54.41 UTC+2 skrev Don Y:
On 5/3/2023 2:42 PM, Lasse Langwadt Christensen wrote:
here the civil registration number is 10 digits, first six is date of birth dd-mm-yy
last four digits encodes the century, and makes a checksum add up
last digit is even for females, odd for males
So, *twins* have identical numbers?

no, some of the last four are different
But that still places a low upper bound on the number of
persons that can be represented. E.g., there are about
3M births, annually, here. Assuming (best case!) of even
distribution throughout the year, that\'s ~10,000 per day
without \"numbering space\" for check digits.

Given that some days are more likely to see higher
birth rates, this suggests 4 digits wouldn\'t be enough
to *simply* number people

yes, it is only about 270 male and 270 female numbers per date
15 years ago they started adding number ranges that doesn\'t pass the old checksum
because they ran out of numbers for jan. 1st 1965 and 1966
so there is now around 3000 male and 3000 female numbers per date

 

[Don Y]

On 5/4/2023 8:26 AM, Lasse Langwadt Christensen wrote:

torsdag den 4. maj 2023 kl. 01.46.10 UTC+2 skrev Don Y:
On 5/3/2023 4:13 PM, Lasse Langwadt Christensen wrote:
torsdag den 4. maj 2023 kl. 00.54.41 UTC+2 skrev Don Y:
On 5/3/2023 2:42 PM, Lasse Langwadt Christensen wrote:
here the civil registration number is 10 digits, first six is date of birth dd-mm-yy
last four digits encodes the century, and makes a checksum add up
last digit is even for females, odd for males
So, *twins* have identical numbers?

no, some of the last four are different
But that still places a low upper bound on the number of
persons that can be represented. E.g., there are about
3M births, annually, here. Assuming (best case!) of even
distribution throughout the year, that\'s ~10,000 per day
without \"numbering space\" for check digits.

Given that some days are more likely to see higher
birth rates, this suggests 4 digits wouldn\'t be enough
to *simply* number people

yes, it is only about 270 male and 270 female numbers per date
15 years ago they started adding number ranges that doesn\'t pass the old checksum
because they ran out of numbers for jan. 1st 1965 and 1966
so there is now around 3000 male and 3000 female numbers per date

Big gaps in the number space as [4-9]????????? aren\'t used.
Ditto ??[2-9]???????, etc.

 

[Don Y]

On 5/4/2023 8:23 AM, Lasse Langwadt Christensen wrote:

torsdag den 4. maj 2023 kl. 09.01.14 UTC+2 skrev upsid...@downunder.com:
On Wed, 3 May 2023 16:44:20 -0700, Don Y <blocked...@foo.invalid
wrote:
On 5/3/2023 4:13 PM, Lasse Langwadt Christensen wrote:
torsdag den 4. maj 2023 kl. 00.54.41 UTC+2 skrev Don Y:
On 5/3/2023 2:42 PM, Lasse Langwadt Christensen wrote:
here the civil registration number is 10 digits, first six is date of birth dd-mm-yy
last four digits encodes the century, and makes a checksum add up
last digit is even for females, odd for males
So, *twins* have identical numbers?

no, some of the last four are different

But that still places a low upper bound on the number of
persons that can be represented. E.g., there are about
3M births, annually, here. Assuming (best case!) of even
distribution throughout the year, that\'s ~10,000 per day
without \"numbering space\" for check digits.

Given that some days are more likely to see higher
birth rates, this suggests 4 digits wouldn\'t be enough
to *simply* number people

Some refugee groups are the most likely to cause havoc to this kind of
numbering systems. Some immigrating people:

* might honestly not know their date/year of birth
* try to hide their history by avoid giving correct date of birth
* give incorrect dates/year to try to get some child benefits
* give date/year in some foreign calendar (e.g. Arabic) and the
immigration officer is too lazy to find the corresponding date in
official calendar

These are then stored to have been born on xxxx-01-01. Of course most
stored as January 1st are fake, since only a small fraction is
actually born on New Years Day, but how do you tell the difference ?
Those born in a foreign country and claim xxxx-01-01 as their birth
date are more suspect.

yep, about 15 years ago the system was changed to allow number than
doesn\'t have the checksum, because they ran out of number for 01-01-65 and 01.01.66

Too funny. Like 11/1/1938 in Grover\'s Mill, NJ... <grin>