The question frequently arises as to when aggregated or
anonymized can be disclosed and when even with the aggregation or
anonymization it is likely to disclose information that need to be
protected. Two recent decisions from the Office of the Information and Privacy
Commissioner of Ontario provide some guidance.
In PO-3438 the issue was whether
aggregate information about professional allowances paid by drug
manufacturers to pharmacies could be released. The drug
manufacturers argued that release of the total dollar amounts of
professional allowances that drug manufactures collectively paid to
pharmacies and the percentages of those amounts paid with under the
Ontario Drug Benefit Act or otherwise would disclose confidential
third party information, contrary to s. 17 (1) (a) of the Freedom of Information and Protection of
Privacy Act (FIPPA).
After review the three-part test set out in FIPPA,
the records must reveal information that is a trade secret or
scientific, technical, commercial, financial or labour relations
the information must have been supplied to the ministry in
confidence, either implicitly or explicitly; and
the prospect of disclosure of the records must give rise to a
reasonable expectation that one of the harms specified in paragraph
(a) of section 17(1) will occur.
The adjudicator ruled that, since the information was the total
dollar amounts of the professional allowances and was not linked to
any named drug manufacturer, that is was simply not
"credible" to conclude that the release of the
information could reasonably be expected to result in the harm
envisaged by s. 17 (1) (a).
By contrast, in Order PO-3429 the situation was
different. A requestor had sought access to historical data showing
the length of sentence for individual inmates locked up in
provincial correction institutions from the Ministry of Community
Safety and Correctional Services. The researcher wanted the last
known postal code for each inmate.
The issue under FIPPA was whether the postal
code information would disclose personal information as defined in
FIPPA. In this case, the adjudicator agreed that the information,
even if anonymized, could reasonably be used to identify an
individual offender. The evidence persuaded the adjudicator that
the postal code information could be used to re-identify
individuals and that disclosure of the information, when linked to
other data sets being disclosed, such as length of sentence, could
lead to the identification of individuals. The decision of the
Ministry to refuse to disclose the information was upheld.
This issue of aggregate or anonymized information is a vexing
one for privacy practitioners and these cases show that the answer
is not an easy one. Each case needs to be examined on its own
merits and in light of other information that may be available to
be linked with the anonymous or aggregate data.
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