The PII Problem: Privacy and a New Concept of Personally Identifiable Information

Personally identifiable information (PII) is one of the most central concepts in information privacy regulation. The scope of privacy laws typically turns on whether PII is involved. The basic assumption behind the applicable laws is that if PII is not involved, then there can be no privacy harm. At the same time, there is no uniform definition of PII in information privacy law. Moreover, computer science has shown that in many circumstances non-PII can be linked to individuals, and that de-identified data can be re-identified. PII and non-PII are thus not immutable categories, and there is a risk that information deemed non-PII at one time can be transformed into PII at a later juncture. Due to the malleable nature of what constitutes PII, some commentators have even suggested that PII be abandoned as the mechanism by which to define the boundaries of privacy law.In this Article, we argue that although the current approaches to PII are flawed, the concept of PII should not be abandoned. We develop a new approach called “PII 2.0,” which accounts for PII’s malleability. Based upon a standard rather than a rule, PII 2.0 utilizes a continuum of risk of identification. PII 2.0 regulates information that relates to either an “identified” or “identifiable” individual, and it establishes different requirements for each category. To illustrate this theory, we use the example of regulating behavioral marketing to adults and children. We show how existing approaches to PII impede the effective regulation of behavioral marketing, and how PII 2.0 would resolve these problems.