4 ms·

Here's some backstory, from the 1990s when the Massachusetts' Group Insurance Commission released "anonymized" health data: ''At the time GIC released the data

by jdp23 15y ago

Here's some backstory, from the 1990s when the Massachusetts' Group Insurance Commission released "anonymized" health data: ''At the time GIC released the data, William Weld, then Governor of Massachusetts, assured the public that GIC had protected patient privacy by deleting identifiers. In response, then-graduate student Sweeney started hunting for the Governor’s hospital records in the GIC data. She knew that Governor Weld resided in Cambridge, Massachusetts, a city of 54,000 residents and seven ZIP codes. For twenty dollars, she purchased the complete voter rolls from the city of Cambridge, a database containing, among other things, the name, address, ZIP code, birth date, and sex of every voter. By combining this data with the GIC records, Sweeney found Governor Weld with ease. Only six people in Cambridge shared his birth date, only three of them men, and of them, only he lived in his ZIP code. In a theatrical flourish, Dr. Sweeney sent the Governor’s health records (which included diagnoses and prescriptions) to his office.'' Source: http://arstechnica.com/tech-policy/news/2009/09/your-secrets-live-online-in-databases-of-ruin.ars http://arstechnica.com/tech-policy/news/2009/09/your-secrets...

reinhardt 15y ago
If only 6 people out of 54000 shared Weld's birthday, she was just lucky (not that this invalidates the main point).
- smokey_the_bear 15y ago
  Birthdate includes year
- arohner 15y ago
  Including birth year helps significantly. Assuming an even distribution of births, you'd expect 54000/365 ~ 148/day. Then knowing gender lets you cut that in half. Dividing again by the age distribution of voters gets that down to a reasonable number.
- reinhardt 15y ago
  Edit: Ok ok got it, birthday includes the year, my mistake; no need to keep downvoting
russell 15y ago
I had to deal with the converse of the problem when I was working for a company that ran the vehicle smog checking for the state of Illinois. A driver's license id was composed of birthdate, sex, and some location information (I dont remember exactly what) for the reasons mentioned by jdp23 it worked quite well, except for identical twins, who had the same driver's license id. (Registrations ofter were processed by hand at drug stores. The driver's license was used to disambiguate ambiguous renewals.) The state of Texas complicated things by allowing a family to have the same license plate for all their cars. One family had seven vehicles, all with the same license plate number. Florida would issue the same plate to complete strangers. One man arrested with great drama, because a bank robber (or some such undesirable) had the same (legal) plates. My GF has such a common name that her doctor has to check which one of three she is. The last time she tried to get her driver's license renewed online, she was told she had to go to the DMV in person. She asked why and was told she was a "Code 5". She reported to the DMV and told the woman that she was a Code 5. There dropped jaws and a hurried conference with a supervisor who called Sacramento and had a lengthy conversation with comments like, "Yes I'm sure. She's right here." Finally she got impatient and asked, "What's Code 5?" The clerk said, "You're dead and it was verified by medical personnel." She did eventually get her license renewed. Officially I live with a zombie. It isnt as bad as the movies portray.
- blahedo 15y ago
  > ...for the state of Illinois. A driver's license id was composed of birthdate, sex, and some location information.... It's worse than that: in Illinois the first four characters of your DL ID are your last name's soundex code.
  - hvs 15y ago
    That used to be true for MN as well, but in the time that I moved from MN to IL back to MN (about 13 years), MN dropped that.
  - steve-howard 15y ago
    Do you have a source for this? I think it's pretty cool and I'm wondering if there's a reasonably centralized place for other states' formats as well.
glimcat 15y ago
Never underestimate the power of bored graduate students.

by jdp23 15y ago

reinhardt 15y ago

If only 6 people out of 54000 shared Weld's birthday, she was just lucky (not that this invalidates the main point).

smokey_the_bear 15y ago
Birthdate includes year
arohner 15y ago
Including birth year helps significantly. Assuming an even distribution of births, you'd expect 54000/365 ~ 148/day. Then knowing gender lets you cut that in half. Dividing again by the age distribution of voters gets that down to a reasonable number.
reinhardt 15y ago
Edit: Ok ok got it, birthday includes the year, my mistake; no need to keep downvoting

russell 15y ago

I had to deal with the converse of the problem when I was working for a company that ran the vehicle smog checking for the state of Illinois. A driver's license id was composed of birthdate, sex, and some location information (I dont remember exactly what) for the reasons mentioned by jdp23 it worked quite well, except for identical twins, who had the same driver's license id. (Registrations ofter were processed by hand at drug stores. The driver's license was used to disambiguate ambiguous renewals.) The state of Texas complicated things by allowing a family to have the same license plate for all their cars. One family had seven vehicles, all with the same license plate number. Florida would issue the same plate to complete strangers. One man arrested with great drama, because a bank robber (or some such undesirable) had the same (legal) plates. My GF has such a common name that her doctor has to check which one of three she is. The last time she tried to get her driver's license renewed online, she was told she had to go to the DMV in person. She asked why and was told she was a "Code 5". She reported to the DMV and told the woman that she was a Code 5. There dropped jaws and a hurried conference with a supervisor who called Sacramento and had a lengthy conversation with comments like, "Yes I'm sure. She's right here." Finally she got impatient and asked, "What's Code 5?" The clerk said, "You're dead and it was verified by medical personnel." She did eventually get her license renewed. Officially I live with a zombie. It isnt as bad as the movies portray.

blahedo 15y ago
> ...for the state of Illinois. A driver's license id was composed of birthdate, sex, and some location information.... It's worse than that: in Illinois the first four characters of your DL ID are your last name's soundex code.
- hvs 15y ago
  That used to be true for MN as well, but in the time that I moved from MN to IL back to MN (about 13 years), MN dropped that.
- steve-howard 15y ago
  Do you have a source for this? I think it's pretty cool and I'm wondering if there's a reasonably centralized place for other states' formats as well.

glimcat 15y ago

Never underestimate the power of bored graduate students.