Title
The re-identification risk of Canadians from longitudinal demographics.
Abstract
The public is less willing to allow their personal health information to be disclosed for research purposes if they do not trust researchers and how researchers manage their data. However, the public is more comfortable with their data being used for research if the risk of re-identification is low. There are few studies on the risk of re-identification of Canadians from their basic demographics, and no studies on their risk from their longitudinal data. Our objective was to estimate the risk of re-identification from the basic cross-sectional and longitudinal demographics of Canadians.Uniqueness is a common measure of re-identification risk. Demographic data on a 25% random sample of the population of Montreal were analyzed to estimate population uniqueness on postal code, date of birth, and gender as well as their generalizations, for periods ranging from 1 year to 11 years.Almost 98% of the population was unique on full postal code, date of birth and gender: these three variables are effectively a unique identifier for Montrealers. Uniqueness increased for longitudinal data. Considerable generalization was required to reach acceptably low uniqueness levels, especially for longitudinal data. Detailed guidelines and disclosure policies on how to ensure that the re-identification risk is low are provided.A large percentage of Montreal residents are unique on basic demographics. For non-longitudinal data sets, the three character postal code, gender, and month/year of birth represent sufficiently low re-identification risk. Data custodians need to generalize their demographic information further for longitudinal data sets.
Year
DOI
Venue
2011
10.1186/1472-6947-11-46
BMC Med. Inf. & Decision Making
Keywords
Field
DocType
random sampling,cross section,health informatics
Population,Data mining,Confidentiality,Risk assessment,Demographics,Postal Code,Health informatics,Unique identifier,Medicine,Custodians
Journal
Volume
Issue
ISSN
11
1
1472-6947
Citations 
PageRank 
References 
11
0.80
9
Authors
6
Name
Order
Citations
PageRank
KHALED EL EMAM12469156.01
David Buckeridge2152.42
Robyn Tamblyn311122.43
Angelica Neisa4564.26
Elizabeth Jonker5323.46
Aman Verma6284.71