Principle O6: retaining data

Data collected for a study up to the point a study participant stops providing data should be used in the study analysis, and kept with the other study data until the study is over.

The data should also be made available for legitimate additional research in line with participant consent and appropriate approvals.

Data collected for research studies up to the point a study participant stops providing data should be used in the study analysis, included in the reported study results and kept until the study is completely over.

This includes the archiving period after the study analysis, when data is kept in case the results need to be checked.

If study participants could get the study data already collected about them deleted, or not used in the study analysis, this could seriously harm the study and its results.

For example, it might mean the study no longer has enough data to be able to reliably answer the research question. This might mean that the study results are unclear about whether or not a new treatment is better, when in reality it is better.

If lots of data was lost in this way from one of the treatment groups it might mean the study had misleading results.

This approach is allowed by laws about how people’s data can be used in the UK and the EU. These laws recognise the need to protect research, particularly when it is being done in the public interest. Laws in other areas of the world may vary and should be followed appropriately.

While in many situations under UK and EU law, individuals can get organisations that hold data about them to delete that data, this right is limited when it comes to data that is being used for research.

This limitation on participants’ rights only applies to legitimate research with the appropriate ethical approvals (where required). It also only applies when the limitation has been clearly explained to participants before they joined the study.

Data collected for research studies is routinely made available to other researchers at the end of the study for additional research.

This is only done for valid research with appropriate approvals (where required), and usually done in such a way that individual study participants cannot be identified by anyone outside the original study team.

Collecting data for research studies takes a lot of time and effort, and this data sharing is one way to make the most of the effort involved. The data that is made available in this way should include data collected up to the point that an individual says they want to stop participating in a study, as long as this is in line with what they have consented to.

Other important considerations

In some specific and rare situations data already collected may need to be deleted for legal or other reasons.

Some specific types of research (for example, interview-based ‘qualitative‘ research) sometimes give participants the option to have their data deleted for a period before the data is analysed, particularly if the data is about very sensitive topics.

In some other types of research study (for example in psychology), it is necessary to give participants false or misleading information during the study in order to carry out the research and obtain reliable results.

These sorts of studies can only go ahead if an independent ethics committee agree that the deception is necessary for the research. In these studies, participants need to be told about the deception at the end, and they should be given the chance to have their data deleted by the researchers, if they want this.

Wherever possible, the potential for situations where data deletion could be allowed should be considered in advance (particularly in relation to the specific group of people who might take part in the study) and prepared for when the study is being designed.

In some research, data can be fully anonymised, so that it is no longer possible for anyone to say who the data is about. In these cases, it is no longer possible to delete individual participants’ data, because it isn’t possible to say which data is about them.

See also:

Relevant PeRSEVERE resources:

Relevant PeRSEVERE principles:

  • This limitation on participants’ rights to have data about them deleted may be easier for them to accept if they are aware that collecting less data than planned can have an impact on the quality of study results. See principle O3 for more on this.
  • Participants must be informed of this limitation on their rights before they agree to take part in the study. Under UK and EU data protection law, it is also a legal requirement that they are informed of this. See principle D3 for more details.
  • Data collection: this means the act of adding relevant data onto study forms or systems, to make the data available for running and analysing each study. It does not refer to any separate tests or procedures used to generate the data in the first place.
  • Treatment groups: many types of research study involve comparing groups of participants taking different treatments, to see which treatment which might be better.  
  • Qualitative research: this term refers to research that collects and analyses data that is not made up of numbers and figures. It can often involve analysis of the contents of interviews with research participants, or of written texts.