Multiple Identities—Linked or Not

Most people already have multiple identities. To your bank, you are your account number. To your motor vehicles bureau, you are your driver’s license number. And to your credit card company, you are your credit card number. For particular purposes, these numbers are your identity; the fact that each may (or may not) be held in your name is irrelevant. The name becomes important if it is used as a way to link these numbers and their associated records. How many people share your name? Can (or should) there be a key value to link these separate databases? And what complications arise when we consider misspellings and multiple valid forms of your name (with and without middle initial, with full middle name, with one of two middle names if you have two, and so forth)?

Moreover, what if you have a commonly used name, or your name changes at some time? Suppose you change your name legally but never change the name on your credit card. Then your name cannot easily be used as a key on which to link. You might try to use a secondary characteristic as verifier, such as address. However, address presents another risk: Perhaps a criminal lived in your house before you bought it. You should not have to defend your reputation because of an unrelated previous occupant. We could match on date, too, so we connect only people who actually lived in a house at the same time. But then group houses or roommates of convenience present additional problems. As computer scientists, we know that programming all these possibilities is possible but requires careful and time-consuming consideration of the potential problems before designing the solution. Alas, we know that too frequently such unusual but critical peculiarities are not considered until after code is developed and installed, and then each exceptional case is considered alone and often in haste. We can see the potential for misuse and inaccuracy.