The re-identification risk of Canadians from longitudinal demographics

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusions</p> <p>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.</p

Unique on Facebook: Formulation and Evidence of (Nano)targeting Individual Users with non-PII Data

Proceedings of: ACM Internet Measurement Conference (IMC '21), November 2-4, 2021, Virtual Event, USA.The privacy of an individual is bounded by the ability of a third party to reveal their identity. Certain data items such as a passport ID or a mobile phone number may be used to uniquely identify a person. These are referred to as Personal Identifiable Information (PII) items. Previous literature has also reported that, in datasets including millions of users, a combination of several non-PII items (which alone are not enough to identify an individual) can uniquely identify an individual within the dataset. In this paper, we define a data-driven model to quantify the number of interests from a user that make them unique on Facebook. To the best of our knowledge, this represents the first study of individuals’ uniqueness at the world population scale. Besides, users’ interests are actionable non-PII items that can be used to define ad campaigns and deliver tailored ads to Facebook users. We run an experiment through 21 Face-book ad campaigns that target three of the authors of this paper to prove that, if an advertiser knows enough interests from a user, the Facebook Advertising Platform can be systematically exploited to deliver ads exclusively to a specific user. We refer to this practice as nanotargeting. Finally, we discuss the harmful risks associated with nanotargeting such as psychological persuasion, user manipulation, or blackmailing, and provide easily implementable countermea-sures to preclude attacks based on nanotargeting campaigns on Facebook.This research received funding from the European Union’s Horizon 2020 innovation action programme under the PIMCITY project (Grant 871370) and the TESTABLE project (Grant 101019206); the Ministerio de Economía, Industria y Competitividad, Spain, and the European Social Fund(EU), under the Ramón y Cajal programme (Grant RyC-2015-17732); the Ministerio de Educación, Cultura y Deporte, Spain, through the FPU programme (Grant FPU16/05852); the Agencia Estatal de Investigación (AEI) under the ACHILLES project (Grant PID2019-104207RB-I00/AEI/10.13039/501100011033); the Community of Madrid synergic project EMPATIA-CM (Grant Y2018/TCS-5046); the Fundación BBVA under the project AERIS; and the Vienna Science and Technology Fund through the project “Emotional Well-Being in the Digital Society” (Grant VRG16-005)

Graphic Katrina: Disaster Capitalism, Tourism Gentrification and the Affect Economy in Josh Neufelds's A.D.: New Orleans After the Deluge (2009)

This article explores the ways in which Josh Neufeld’s documentary comic, A.D.: New Orleans After the Deluge, which was published first online from 2007 to 2008 and then collected in book form in 2009, offers a radical visual commentary on the processes of disaster capitalism and tourism gentrification that have reshaped New Orleans since Hurricane Katrina in 2005. Whilst A.D.’s biblical imagery evokes the proto-corporate language of the ‘blank canvas’ in order to critique regimes of disaster capitalism, its vertical multi-scalar perspectives meanwhile resist the racism of media coverage of the event. Through colouring and other aesthetic choices, the comic also challenges the subsequent propagation of an ‘authentic image’ of New Orleans that promotes tourism gentrification. Where previous critics have emphasised the emotional appeal A.D.’s makes on its readers, I instead discuss the comic’s identification of the structural conditions that have violently impacted the city’s most marginalised inhabitants. Nevertheless, the article qualifies these contentions by acknowledging that A.D. also contributes to an ‘affect economy’ that has exacerbated the privatisation of previously public infrastructure and social services, often to the detriment of pre-Katrina residents simply trying to return to their city