The Participant Is the Instrument

Part of Decentralized Trials (DCT) Training: ePRO and Participant-Entered Data.

About 2 minutes. Free, in your language, no account needed.

ePRO measures what the participant reports

Not what is true, and not what a clinician would have recorded. That is the point of it: for pain, fatigue, nausea and mood, the participant's account is the outcome.

This makes the instructions, the timing and the wording part of the measurement.

Do not interpret for them

A participant asks what counts as moderate. The helpful answer feels like an explanation.

Any explanation you give becomes part of their answer, and a different coordinator will explain it differently. Point them back to the instrument's own wording and record that they asked.

Systematic coaching across participants is how a patient-reported endpoint stops measuring the patient.

Timing is part of the design

A morning diary completed at night is a different measurement. A weekly recall completed two weeks late is not a recall of that week.

Most systems timestamp entries and enforce windows. Where they do not, late entries must be identifiable rather than silently accepted.

Backfilling destroys the instrument

A participant who missed four days and wants to fill them in is offering reconstruction, not recall.

Missing entries stay missing. That is a real answer and the analysis can handle it. Invented recall cannot be distinguished from real recall once it is in the dataset.

Watch for the pattern that is too good

A participant with a perfect completion record, always at the same minute, reporting an identical score, may have a reminder habit rather than a stable symptom.

It is worth a gentle question. Perfect compliance is sometimes exactly what it looks like and sometimes a proxy completing it.

Non-completion is information

A participant who stops completing diaries may be unwell, may have lost the device, or may have disengaged. All three matter and they need different responses.

Chase it as a clinical signal, not as a compliance metric.

Never enter data on their behalf

Even with them on the phone reading answers out, if the study defines it as self-administered. Record that route separately if it is permitted at all.