03/02/2014 08:56 EST | Updated 05/02/2014 05:59 EDT

Can Metadata Solve Washroom Graffiti?

I learned a while ago about a school that had a problem with particularly nasty racist graffiti. From time to time, the ugly words and images appeared in a washroom on the school's third floor. The administration was distraught. But they soon came up with a solution. Rather than address the issue of racism, or spend time finding out why someone thought such things were acceptable, the administration devised a plan.

The doors to all the washrooms would be locked. If any student needed to use the facilities, he or she would have to go to the office and sign out the key to the only available washroom which was on the first floor. The sign out book recorded the students' names, their classes, the times they picked up the key, whether they had seen any graffiti in the washroom and the time the key was returned. There were no cameras and no adults patrolling in or near that one washroom, therefore, the administration felt that no one's privacy was at risk.

A math teacher who heard about this approach thought it was a great idea. What could be better than a math lesson that involves students' day to day experiences?

She described how, based on the records kept, she could develop a graph-making assignment for her class. Each day's sign out sheet could be plotted out according to which class the students came from, to male or female students, to how many used the washroom, how many times each user used the facility and how long they spent between picking up the key and returning it.

Of course there were no data on what each person DID in the washroom, but a great deal of information could be gleaned from the simple sign out sheet, and much of it was very personal, indeed.

The math teacher thought it would be great to assign her students a research project based on their graphs. Could they report on whether boys or girls used the washroom more frequently? Could they report on which classes had the greatest number of washroom users? What about the classes whose students stayed in the washroom the longest? What time of day did the washroom get the most use? Was the washroom used more on certain days than on others? Could they correlate time of day with certain students' washroom usage? Could they zoom in even closer? Which student used the washroom most frequently? Which one tended to stay the longest?

The math teacher and her students would end up with a study based on metadata collected for another purpose entirely. Just like the Communications Security Establishment Canada (CSEC) and the U.S. National Security Agency (NSA) who use information gathered from our electronic devices to find "suspicious" patterns, the school had succeeded in collecting information that had not been intended to target any particular individual -- but could be used to reveal an enormous amount that most people would prefer to keep to themselves.

So instead of reassuring yourself that since you have nothing to hide, collection of metadata won't reveal anything interesting about you, ask your children how they feel about the proposed washroom math lesson. Then you can both stand up for your rights.