Principle M1: Informative data collection about participation changes

Data about study participation changes should be recorded in a standardised way and include enough detail to usefully inform study management, analysis and reporting.

Data should include, when available, meaningful information about when and why the participant has reduced or stopped their participation.

Collected data should also clearly communicate the participant’s wishes, including which elements of study participation they want to stop, and which they have agreed to continue.

There are several reasons why researchers running a study should collect good quality data about the number and nature of participation changes occurring while the study is ongoing.

Good quality data is essential for study analyses. It is also important for clear reporting of studies and so that researchers running and overseeing studies can keep an eye on any trends in participation changes.

Collecting data in a standardised way where possible is important, so that data from different places (within a study or even between studies) can be more easily used, combined and compared.

It can be particularly important for study analyses to know why participation changes have occurred. This is so that researchers analysing the data can understand how the participation changes might have affected the study results.

We know that study participants have the right to stop participating without giving a reason, and so don’t always give one.

However, when participants have made an informed, freely-given decision to provide a reason to the researchers, this should be collected and used to inform study analyses, possibly based on some sort of standardised list.

Information about reasons for participation changes can be sensitive and personal. Researchers should therefore only collect as much detail as necessary for the purposes of analysing and reporting on the study.

Whenever the participation change is the participant’s choice, a clear record of participants’ wishes allows clarity for researchers about what further study activity will take place for a participant, if any.

Researchers running studies should make reasonable efforts to find out exactly what a participant wants when they say they want to stop or reduce their participation.

If, despite these efforts, the participant has not given detailed information about their wishes, the data recorded for study purposes should make this clear. This can be important when thinking about, for example, whether any data from routine healthcare visits could be collected for use in the study.

Researchers should also check and make a note of whether or not the participant wants to find out the results of the study when they are available (as well as any other updates that might be available later in the study), regardless of whether the participant completed all parts of the study or not.

Researchers should only collect as much data and as much detail as they need for the purposes mentioned above.

They should decide what data they need to collect for their specific study, in line with reporting guidelines, core outcome sets and other agreed approaches.

See also:

Relevant PeRSEVERE resources:

Relevant PeRSEVERE principles:

  • Data collection should be planned with the knowledge that participation can stop, reduce or change, and the data collected should reflect this complexity. See principle O1 for more about this.
  • Data collection about participation changes should make a difference between participants saying they want to stop taking part, and researchers losing contact with participants. See principle O4 for more on this.
  • Clear data about participants’ wishes is important so that researchers know if participants are happy for data collection to continue or not. See principle O5 for more on this.
  • Data collection should be informed by the study protocol and the statistical planning. See principles D2 and R1 about this.
  • Collection of good quality data about participation changes relies on researchers being trained and supported to collect it. See principle D6 for more on this.
  • Good quality data about participation changes is essential for oversight of studies while they are ongoing, and for clear reporting of studies when they are finished. See principles M2 and R2 about 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.
  • We use the term “running” a study here to mean all activity involved in making a study happen, including getting the relevant approvals to start the study, working with the NHS and other organisations to set up study sites where participants will be recruited, making decisions about the management of the study, collecting and processing study data, and so on.
  • Reporting guidelines: these give researchers expert guidance about how to share results of their studies in a clear and consistent way.
  • Core outcome sets: these are things that experts have agreed should always be measured in similar sorts of studies, and included in the results of these sorts of studies.