Understanding identifiability in secondary health data.

Secondary health data are becoming important sources of information for health research. Unfortunately, there are few national guidelines outlining clear criteria for data custodians when adjudicating requests for access to these data. This presents a particular challenge to researchers and even public health officials interested in multi-jurisdictional analysis of health data. While some of the problem in developing consistent national standards may stem from differences in provincial privacy law, it may also be the result of imprecise terminology, particularly around the concept of identifiability. This commentary discusses the differences between identifiability and self-identification with the hope of contributing to a broader discussion establishing national guidelines for the use of secondary health data in research.