Principle O5: continuing data collection

Study data collection should continue until a study participant explicitly tells researchers that they want it to stop.

This approach is valid and fair only if it is made clear to participants before they join the study, including how they can express a wish for stopping data collection, if that is what they want.

Researchers should also make all reasonable efforts to find out exactly which aspects of study participation a participant wants to stop, if they express the wish to stop or reduce their participation. Any further data collection must still be done in line with the informed consent that participants previously gave.

This approach can also be applied to other aspects of participation, as long as those aspects are necessary and have a relatively low impact on participants, and as long as any further activity is done according to the conditions mentioned in this principle.

If study participants want to stop their data being collected for the study, then it should stop. However, if they do not say they want it to stop, then it should not.

This protects the quality of the research because the more of the relevant data about each participant is available for the study analysis, the better it is for the analysis.

When a participant says they want to stop taking part in a study, it could be because they do not want their data collected anymore, but it could be for other reasons. Stopping participation can mean a variety of things, and not all of these mean data collection needs to stop.

For example, a study might require a participant to attend extra hospital visits alongside some routine (non-study) visits that would happen anyway, even if they weren’t in the study.

After a while, a participant might find the study visits a burden and say that they no longer want to do them. They will continue to attend the routine visits as part of their usual care. Some data from the routine visits could be useful to the study.

If at all possible, the researchers should ask the participant if they are happy for their data from the routine visits to be used for the study.

If the participant only says that they want to stop the study visits and doesn’t say anything about not wanting their routine health data to be used for the study (even after having been asked their view on this), then the data should still be collected. They can still at any time say they don’t want this to happen anymore.

If the participant does want data collection to stop, data from study visits or other events occurring before they made their decision can still be used for the study, as the participant had not yet made their decision at that point.

Data from those previous points in time can also still be added to study forms or study databases, if this has not happened yet.

The details of this approach should be made clear to study participants before they agree to take part in a study.

They should therefore be aware that until they say they want their data to stop being collected for the study, it will still be collected. However, it should also be clear that they can say they want data collection to stop at any time.

Researchers must also make all reasonable efforts to find out what participants want when they say they want to stop taking part in a study, including to find out if participants are happy for their data to be collected from routine healthcare visits.

It may be fair to remind participants of any aspects of their participation that are still continuing at the time they stop or reduce their participation, if there is a suitable opportunity to do this.

It is possible for this sort of approach to be applied to other aspects of participation, meaning that those aspects can continue until a participant explicitly says they want them to stop.

Any such aspects or activities must be necessary, for example in running the study, protecting study integrity or protecting the safety of patients in or outside the study.

The activities must not involve unexpected or unwanted burden, intrusion or inconvenience to the participant, and they must continue to be done in the way described to participants when they previously gave informed consent.

All the other conditions of using this approach (as mentioned above) must also be in place in order for it to be valid and fair.

The sorts of other study activities that might be suitable for this approach include continuing use and storage of biological samples, or continuing access for researchers to review participants’ medical notes for the purposes of checking that the study has been run correctly (where this access is based on participants’ initial consent).

Researchers should still take a cautious approach to applying this principle – regarding further data collection or anything else.

This might mean that, when there is no reliable information available about what the participant wants to do, researchers should assume that participants would want study activities to stop when continuing those activities would not reasonably be expected by the participant.

There may also be sensitivities around particular scenarios (for example, related to worsening mental health or capacity to consent) that might lead researchers to conclude that it would not be appropriate to continue study activities without active confirmation that participants are happy with it.

Other important considerations

Different considerations will apply in situations where individuals have lost capacity to give informed consent: applicable laws and guidance should be followed in these cases.

There may also be cases where some data collection needs to continue even after a participant has said they would like study data collection to stop.

For example, data about the safety of treatments needs to be collected by law in some drug studies (also known as clinical trials of ‘investigational medicinal products’, or ‘CTIMPs’) and this needs to continue even after a participant says they do not want their data to be collected for the study anymore.

In studies where this sort of rule applies, it should be made clear to participants before they join the study and it should also be described in the study protocol.

See also:

Relevant PeRSEVERE resources:

Relevant PeRSEVERE principles:

  • When a participant wants to stop or reduce their participation, this does not automatically mean they must stop all aspects of participation. In fact, participation can stop, reduce or change. See principle O1 for more on this.
  • Participants’ decisions about whether or not data collection continues should be informed by their knowledge of the consequences of their decision. See principle O2 for more about this.
  • Participants should receive clear and balanced information, before they agree to take part in a study, about what will happen if they decide to stop or reduce their participation later on. This should make clear that data collection will continue until they ask for it to stop. See principle D3 for more on this.
  • The discussions about the participant’s wishes should form part of the ongoing dialogue about their participation. See principle D5 for more on this.
  • 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.
  • Capacity or capacity to consent means a person’s ability to make decisions for themselves. In the context of research, it means a person’s ability to give informed consent to take part in a study. Some people have a varying or reduced ability to make decisions for themselves, for example people with dementia. By law, children also do not have capacity to consent, so their parents or guardian need to consent (or not) on their behalf.
  • Study protocol: this is the document (or set of documents) that describes why a study is needed, what it aims to achieve and how it should be run.