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Research Using Secondary Data Only

This page is a guide to be used when the only data comes from secondary use of data, though it may provide tips for those working on a project for which secondary use of data is a component of a larger project.

“Secondary use refers to the use in research of information originally collected for a purpose other than the current research purpose” TCPS2

This could mean data collected by you or another researcher for a different study, or information/material collected for a non-research purpose (e.g. course grades, employment records, registrar data, etc.)

In most cases, you need REB approval to conduct research using secondary data


  • If the secondary data to be used has always been anonymous (see distinctions below) and the research won’t generate identifiable information (Art 2.4). This is more common with biological materials and identifying people due to genetics, but is potentially possible in other studies, for example ones with a good deal of indirectly identifying variables or anonymous reporting of actions during public events.
  • If the secondary data is publicly available via legislation, or is in the public domain and the involved individuals have no reasonable expectation of privacy (Art 2.2)


Anonymous The data has never had identifiers attached to it.  Not even the researcher(s) or organization that collected the original data knows who provided the data. This is rare, often only in surveys.
Anonymized At some point, the data DID have identifiers attached, but they have been irrevocably stripped from all copies of the data.
De-identified Identifiers are not directly connected to the data, but the researchers or data custodians have methods to determine who provided what information, such as a study key.
Identified The data is being stored with identifiers directly connected to the data.

If researchers are receiving access to identifiable data or de-identified data (and have the means to re-identify), the expectation is researchers will seek consent from the people the data is about before using it for research.  Exceptions to this expectation are outlined in Art 5.5A (all criteria need to be met):

  1. identifiable information is essential to the research;
  2. the use of identifiable information without the participants’ consent is unlikely to adversely affect the welfare of individuals to whom the information relates;
  3. the researchers will take appropriate measures to protect the privacy of individuals and to safeguard the identifiable information;
  4. the researchers will comply with any known preferences previously expressed by individuals about any use of their information;
  5. it is impossible or impracticable to seek consent from individuals to whom the information relates; and
  6. the researchers have obtained any other necessary permission for secondary use of information for research purposes.

The onus is on the researcher to prove that they meet this criteria.  An example would be that MREB is likelier to accept that it is impracticable to contact students from 5 years ago to request permission to use course assignments for a research study than they are to accept that it is impracticable to contact students that finished the course last month.

Note that Art 5.5B clarifies that secondary use of non-identifiable data does not require consent but does require REB review.  This applies to anonymized data and to de-identified data when the researchers receiving the data from the data custodian do not have access to a study key (or any method to re-identify).

Unique requirements when conducting research with secondary use of data originating from an Indigenous community or peoples is covered in Articles 9.20-9.22.

In addition to these ethical requirements, the secondary use of data may be subject to laws, regulations and institutional policies.  It is the researcher’s responsibility to ensure that they have considered these potential requirements.

For tips on how to complete an application that only uses non-identifiable secondary data in MacREM, please review our guide here.

Please contact us at for guidance when working with secondary data.