Saturday, August 3, 2013

How unique are you? Your Zip code knows.

When I am out shopping and ready to checkout the clerk asks me for my Zip code. My family readily gives out such information and often apologizes to the clerk when I refuse to give out my Zip code. When I respond with that is personal information my reply is just eyes rolling with your just being grumpy. Of couse there is some truth in that. But still we have the question is how much information can they(retail store) get by knowing my Zip code? The answer is a lot.

Famed Harvard Professor Latanya Sweeney who has done pioneering work on data privacy has a web site where you can now test your uniqueness. Her site asks for your gender, birthdate and Zip Code. Remember the retail store has an advantage because they have your name and Zip code. Give it a try. You might find that you not as unique as you think you are and using your Zip code really can help identify you and in most cases with 100% accuracy.

Dr. Sweeney explains that “365 days in a year x 100 years x 2 genders = 73,000 unique combinations, and because most postal code have fewer people, the surprise fades”.

Here is a sample output using a made up person…
74012 (pop. 57526) Male Birthdate 12/13/1987 Easily identifiable by birthdate (about 1) Birth Year 1987 Lots with your birth year (about 378) Range 1987 to 1991 Wow! There are lots of people in your age range (about 1894)

A lot of retailers today use services like GeoCapture. This service produced by Harte-Hanks ( simply captures your name from your credit card and with the clerk entering your Zip code into the POS during the transaction. Using the GeoCapture service your store matches the collected information to a comprehensive consumer database to return an address.

Beside your address GeoCapture can…

  • Identify customers, understand purchase behavior, and follow up with dynamic, personalized marketing.
  • Provides customer contact information and purchase history.
  • Extensive, proprietary matching logic and nickname tables identify customers easily with accuracy rates close to 100%.
  • Can be used in conjunction with Reverse E-mail Append for customer identification.

Here is the PDF from Harte-Hanks that describes services offered to retail stores. Of course if you shop in your own Zip code and the clerk enters the store Zip code. They got you.

Ok here are some simple proven ways to help protect your privacy.

  • 1. Sign out of online accounts when not using them, Hotmail, Facebook, etc. (This is becoming more difficult with always on mobile apps).
  • 2. Don’t give out personal information when shopping.
  • 3. Encrypt your hard drive on your computer.
  • 4. Turn on 2-step authencation for all app that provide this. Gmail does.
  • 5. Pay cash for embarrassing things.
  • 6. Change your Facebook settings to Friends Only.
  • 7. Clear your browser history and cookies on a regular basis.
  • 8. Use an IP masker.
  • 9. Set and use your passcode on all of your wireless devices.
  • 10. Remember everyone now carries a phone with a camera. If you do some something stupid it is very likely someone took a picture of it and posted it on the Internet.

I thought this was a cool site and I wanted to share it with you. Smile your on camera, maybe.