SS# similarity-- what are the chances?! archived

Don't know about that - but did you know that the beginning of the sequence once signified the area you were born?

http://www.usrecordsearch.com/ssn.htm
http://www.ssa.gov/employer/stateweb.htm

Between individuals it as you note about 1 in 10k. Probability within same family is higher rather than lower- if you have 1000 kids, for example, your probability would be 1 in 10.

Freakshow for sure though. Will probably cost you some phone calls and lots of "yeah yeah we're sure, we get that all the time".

Joy, I did! But I didn't realize the numbers don't signify birth location anymore. My big girl is 2010 and her numbers show she's from NY but the baby is 2014 and is "unlisted."

Jackson, seriously. I had to take pictures of their cards just to prove to my husband it wasn't a transcription mistake.

Wouldn't it be 1 in 100k? Hypothetically, 100k people have a last 4 of 6789 right?

000-00-6789
000-01-6789
000-02-6789
etc

I'm not sure what the "first" prefix is - probably not 000 though.

Edited because I was completely wrong...

My best friend/college roommate/maid-of-honor was born in Texas. I was born in Iowa.

One day when we were standing together in line for "adds and drops" of college classes we discovered our SS#'s were off by 1 number in the third position. (College ID#'s used to be your SS#. We even printed our SS# on our checks back in the day.)

The coincidence still gives me goose bumps. We are roughly the same age and I think we both applied for our Social Security cards when we were 15 years old so that we could get jobs at 16 but it is still weird as hell.

Ah! State where card was issued makes more sense....
http://www.mrfa.org/ssn.htm

My brother and I have SS#s that start the same - the first five digits are identical, the last four are different. I think my parents got them at the same time, even though we are years apart in age, which I thought accounted for this.

This thread prompted my to take a look at my twin daughters' SS#s. Like my brother and I, the girls have the first five digits in common.

When we bought our first house my wife had a credit problem - someone with her same maiden name and birthday (different years) had a bunch of debt. Her SSN was the same but for 2 digits. It was very strange.

This is math. With the last 4 giving you 10,000 options ranging from 0000 to 9999. It does not matter if it is a random person or if it is someone in the family (provided that they did not get their cards at the same time and location). the odds are one in 10,000.

My daughter and I both start with the same three numerals and my son and his father also start with the same three,albeit different than my, numerals. Some of us were born in the Bronx others in Manhattan. Weird? Or explainable?

How old are the kids? You can always explain to them that "one of you is a spare" and let them figure out who's who!

I'm loving these random SSN stories! I had a feeling 1/9,999 is what it is whether it's across the whole population or our little family, it just feels so much more unlikely within a family of two kids! The first 5 digits are different; its just the last four (that everyone uses for identification etc!) that are the same.

I'd guess that the chances of having the first three digits being the same are a lot higher if you were born in the same state, at least when they still assigned your number according to where you were born.

afa said:

I had a feeling 1/9,999 is what it is whether it's across the whole population or our little family, it just feels so much more unlikely within a family of two kids!

I'm terrible at math and statistics, but I have to agree. If it's a 1/10,000 chance that any two cards will have the same last four digits, period, it seems there should be an even lesser chance that those two cards should land in the same family.

For instance, there's a 1/365 chance that any two people will share the same birthday, but it seems a lot less frequent that two siblings (not counting twins) will share the same birthday. Otherwise that would occur in every 365th family or so, and I bet it doesn't.

But again, I know not what I speak of; it just doesn't feel right.

What are the chances that my friend and I have 8 of the 9 digits the same?
If the first three digits have to do with location of issue we will have that commonality except that it was in that section where we differed!

Interesting article from a few years ago about how it's not too difficult to reverse engineer a Social Security number with a few bits of info.

"Given a state and birth date, Acquisti and Gross were able to predict correctly all nine digits in an S.S.N. in 1,000 attempts or fewer, 8.5 percent of the time, which renders a sizable percentage of S.S.N.'s about as easy to crack as a three-number PIN. "


http://query.nytimes.com/gst/fullpage.html?res=9E03E7DC1E39F930A25751C1A96F9C8B63

RobB said:

Wouldn't it be 1 in 100k? Hypothetically, 100k people have a last 4 of 6789 right?

000-00-6789
000-01-6789
000-02-6789
etc

I'm not sure what the "first" prefix is - probably not 000 though.

Wouldn't it actually be 1 in a million (or 999,999,999) since we are talking about a 9 digit number 999 99 9999 ??

joy said:

Don't know about that - but did you know that the beginning of the sequence once signified the area you were born?

http://www.usrecordsearch.com/ssn.htm
http://www.ssa.gov/employer/stateweb.htm

Is that no longer true? My kids numbers are both in that NJ range. And my/my spouse's are in the TX range. (My sister and I have sequential SSNs because, in those days, people didn't usually get them at birth. My father applied for both of ours together when he opened up college funds for us as young children and needed SSNs for those accounts.)

Sundays said:

For instance, there's a 1/365 chance that any two people will share the same birthday, but it seems a lot less frequent that two siblings (not counting twins) will share the same birthday. Otherwise that would occur in every 365th family or so, and I bet it doesn't.

I know someone who had two kids, neither was induced or scheduled, on the same day in different years. When I mentioned that in conversation to someone they related they they and a sibling also shared the same birthday on different years. It does happen.

sac said:

joy said:

Don't know about that - but did you know that the beginning of the sequence once signified the area you were born?

http://www.usrecordsearch.com/ssn.htm
http://www.ssa.gov/employer/stateweb.htm

Is that no longer true? My kids numbers are both in that NJ range. And my/my spouse's are in the TX range. (My sister and I have sequential SSNs because, in those days, people didn't usually get them at birth. My father applied for both of ours together when he opened up college funds for us as young children and needed SSNs for those accounts.)

They changed it very recently, my neice born in 2010 has the old style number, my son born in 2012 has the new "randomized" number.

cppkqp said:

My brother and I have SS#s that start the same - the first five digits are identical, the last four are different. I think my parents got them at the same time, even though we are years apart in age, which I thought accounted for this.

This was common. It used to be that you didn't get a social security card until you needed it for a job or a passport. Now they are assigned at birth.

In doing family research two members of my husband's great grandparents applied for their cards on the same date, their numbers match for the first eight digits.

@sac, I think the first numbers signify the area you lived in when you requested a card. I got a Texas card even though it was not my birthplace.

kmk said:

@sac, I think the first numbers signify the area you lived in when you requested a card. I got a Texas card even though it was not my birthplace.

Sounds right. In my case and my kids' cases, it was the same.

Re requesting SS# at birth, I think this started when the federal government started requiring the child's SS# in order to take a dependent deduction on your taxes. That wasn't the case when most of us were children. I guess it just worked on the honor system then.

I have to pull up the SS page and confirm, but I believe that it used to be that the first three numbers were simply where the card was applied for, but in later years the first three numbers changed to signify where the applicant was born.

spontaneous said:

I know someone who had two kids, neither was induced or scheduled, on the same day in different years. When I mentioned that in conversation to someone they related they they and a sibling also shared the same birthday on different years. It does happen.

I'm sure it does, but I think if it actually happened to every 365th family, as the math would suggest, it would be less noteworthy. For instance I've seen somewhere there are 8452 households in Maplewood. If every 365th household had it happen there would be 23 such families in Maplewood alone. I'm having a hard time to believe there are, or such stories would be far more common.

While not siblings I was born on my great grandfather's birthday. Unfortunately he passed away about one month before I was born so he never knew.

We gave our daughter a somewhat common firstname at birth and one of my family's surnames as a middle name. Later I realized that I had forgotten I had a great aunt with the same name + surname.

It was years before we discovered that my daughter was born on the same date as my great aunt EXACTLY 100 years later! Spooky!

http://www.ssa.gov/policy/docs/ssb/v45n11/v45n11p29.pdf

I was slightly wrong about the first three numbers, it used to be where the card was issued, then it changed to where the applicant lived but was not necessarily where they were born. From the above pdf.

Until 1972, the area number indicated the location
(State, territory, or possession) of the Social Security office
that issued the number. When the Social Security
numbering system was developed, one or more area
numbers were allocated to each State based on the
anticipated number of issuances in the State (table 1).
Because an individual could apply for an SSN at any Social
Security office, the area code did not necessarily
indicate where the person lived or worked. Since 1972,
the Social Security Administration has been issuing
SSN’s centrally from its headquarters in Baltimore. The
area code now indicates the person’s State of residence
as shown on the SSN application.

That makes sense. I was born in Wisconsin but got my SSN in Texas in 1974-ish when I was 16 and got my first "real" job. My SSN has a Texas area number.