Exempt Category 4

Exempt Category 4 - Secondary research on existing (or public) datasets or biological materials


This category is for secondary research on existing datasets (containing individually identifiable information; e.g. data, documents, records), including publicly available datasets (e.g social media platforms), or existing repositories (containing identifiable bio-specimens) for which consent is not required due to the exemption criteria below.

Note: Secondary research should not be conducted without first obtaining Exempt approval. 

Exempt criteria:

  • Datasets and repositories (sources of individually identifiable information or identifiable bio-specimens) that are already existing or publicly available (e.g. social media). 
  • The information used for the secondary research is recorded by the PI in such a manner that subjects cannot be identified directly or indirectly through identifiers linked to the subjects.
  • For continued use of identifiable data, prior broad consent must have been obtained from the subjects for use in future secondary research;
  • No follow-on contact with the subjects for the secondary research, and no return of individual research results (unless required by law);
  • No re-identification of subjects once anonymised.

To avoid any doubt, the PI/study team members may initially have access to (but not physical possession of) individually identifiable information/data/bio-specimens, but the data/bio-specimens need to be abstracted (or recorded) in such a way that they can no longer be connected to the identity of the subjects. An effective barrier to the identifiable data is required under PDPA.

Research teams are to ensure that the handling of research data meets PDPA, HBRA and other regulatory requirements in Singapore.


  • Secondary research utilizing multiple datasets, where there is a chance of re-identification of subjects, is not eligible. 
  • Prospective collection of additional data through contact with the subject or by any other means. 


Q1: If my existing dataset is already in a de-identified format (e.g. through anonymous surveys, or datasets from publications), do I need to obtain approval under Exempt Cat. 4?
No, as Exempt Cat. 4 is for re-analysing de-identified data from existing datasets containing identifiers.