ABSTRACT
To define and measure the probability of re-identification, it is first necessary to define the concept of identifiability. Most privacy laws treat the identifiability of information as a binary construct: information is either identifiable (personal) or not. The definitions of when information is on one side or the other vary and take into account multiple, and sometimes conflicting, criteria. In this chapter we review the different ways in which identifiability has been characterized and the different factors that have been proposed as important for determining if data is identifiable or not.
