The Supreme Court of Canada has issued its unanimous decision in The Queen v. Philip Morris International Inc. This appeal arose out of an ongoing lawsuit brought by the province of British Columbia against tobacco companies to recover the health care costs associated with tobacco-related illnesses in the province. Similar suits brought by other provincial governments are at different stages across the country. In most cases, the litigation is brought under provincial legislation passed specifically to enable and to structure this recourse.

The central issue in this case concerned the degree of access to be provided to Philip Morris International (PMI)to the databases relied upon by the province to calculate tobacco-related health care costs. PMI wanted access to the databases in order to develop its own experts’ opinions on the nature and extent of these costs, and to challenge the opinions to be provided by provincial experts who would have full access to the databases. Although the databases contained aggregate, de-identified data, the government refused access, citing the privacy interests of British Columbians in their health care data. As a compromise, they offered limited and supervised access to the databases at Statistics Canada Data Centre. Although the other tobacco company defendants accepted this compromise, PMI did not, and sought a court order granting it full access. The court at first instance and later the Court of Appeal for British Columbia sided with PMI and ordered that access be provided. The SCC overturned this order.

This case had been watched with interest by many because of the broader issues onto which it might have shed some light. On one view, the case raised issues about how to achieve fairness in litigation where one party relies on its own vast stores of data – which might include confidential commercial data – and the other party seeks to test the validity or appropriateness of analytics based on this data. What level of access, if any, should be granted, and under what conditions? Another issue of broader interest was, where potentially re-identifiable personal information is sought, what measures are appropriate to protect privacy, including the deemed undertaking rule. Others were interested in knowing what parameters the court might set for assessing the re-identification risk where anonymized data are disclosed.

Those who hoped for broader take-aways for big data, data analytics and privacy, are bound to be disappointed in the decision. In deciding in favour of the BC government, the Supreme Court largely confined its decision to an interpretation of the specific language of the Tobacco Damages and Health Care Costs Recovery Act. The statute offered the government two ways to proceed against tobacco companies – it could seek damages related to the healthcare costs of specific individuals, in which case the health records of those individuals would be subject to discovery, or it could proceed in a manner that considered only aggregate health care data. The BC government chose the latter route. Section 2(5) set out the rules regarding discovery in an aggregate action. The focus of the Supreme Court’s interpretation was s. 2(5)(b) of the Act which reads:

2(5)(b) the health care records and documents of particular individual insured persons or the documents relating to the provision of health care benefits for particular individual insured persons are not compellable except as provided under a rule of law, practice or procedure that requires the production of documents relied on by an expert witness [My emphasis]

While it was generally accepted that this meant that the tobacco companies could not have access to individual health care records, PMI argued that the aggregate data was not a document “relating to the provision of health care benefits for particular individual insured persons”, and therefore its production could be compelled.

The Supreme Court disagreed. Writing for the unanimous court, Justice Brown defined both “records” and “documents” as “means of storing information” (at para 22). He therefore found that the relevant databases “are both “records” and “documents” within the meaning of the Act.” (at para 22) He stated:

Each database is a collection of health care information derived from original records or documents which relate to particular individual insured persons. That information is stored in the databases by being sorted into rows (each of which pertains to a particular individual) and columns (each of which contains information about the field or characteristic that is being recorded, such as the type of medical service provided). (at para 22)

He also observed that many of the fields in the database were filled with data from individual patient records, making the databases “at least in part, collections of health care information taken from individuals’ clinical records and stored in an aggregate form alongside the same information drawn from the records of others.” (at para 23) As a result, the majority found that the databases qualified under the legislation as “documents relating to the provision of health care benefits for particular individual insured persons”, whether or not those individuals were identified within the database.

Perhaps the most interesting passage in the Court’s decision is the following:

The mere alteration of the method by which that health care information is stored — that is, by compiling it from individual clinical records into aggregate databases — does not change the nature of the information itself. Even in an aggregate form, the databases, to the extent that they contain information drawn from individuals’ clinical records, remain “health care records and documents of particular individual insured persons”. (at para 24)

A reader eager to draw lessons for use in other contexts might be see the Court to be saying that aggregate data derived from personal data are still personal data. This would certainly be important in the context of current debates about whether the deidentification of personal information removes it from the scope of private sector data protection laws such as the Personal Information Protection and Electronic Documents Act. But it would be a mistake to read that much into this decision. The latter part of the quoted passage grounds the Court’s conclusion on this point firmly in the language of the BC tobacco legislation. Later the Court specifically rejects the idea that a “particular” individual under the BC statute is the same as an “identifiable individual”.

Because the case is decided on the basis of the interpretation of s. 2(5)(b), the Court neatly avoids a discussion of what degree of reidentification risk would turn aggregate or anonymized data into information about identifiable individuals. This topic is also of great interest in the big data context, particularly in relation to data protection law. And, although it might have been interesting to know whether any degree of reidentification risk could be sufficiently mitigated by the deemed undertaking rule so as to permit discovery remains unexplored territory, those looking for a discussion of the relationship between re-identification risk and the deemed undertaking rule will also have to wait for a different case.