Anticipated no-shows require a controlled standby list
Aliases: standby participant · no-show management · over-recruitment
What it is
Standby recruitment prepares eligible replacements and activation rules for expected cancellations or no-shows within each critical quota. It is not unlimited overbooking or inviting several people and rejecting extras at arrival. Standby participants need their status, notification window, and compensation terms. The aim is schedule resilience without letting last-minute convenience alter sample composition.
Why it happens
Absence is not fully random. Shift work, care, connectivity, transport, and burden make some groups more likely to cancel. Replacing them with whoever answers fastest shifts the sample toward always-available people and can break quotas. Estimating no-shows by channel, time, and group, then drawing standby participants under the same rules, controls both operations and selection.
Studying it
Track invitation, confirmation, rescheduling, cancellation, no-show, and completion by group, channel, time, and notice. Size standby capacity from historical intervals and current constraints rather than a fixed percentage. Prespecify activation order, latest notice, repeated contact, and compensation: unactivated people should not have to remain online or on site, and any standby time the study actually occupies must be agreed in advance and compensated. Report replacements and quota changes.
Where it stops holding
Small, rare, or sensitive studies may not justify extra recruitment and privacy cost. Asynchronous remote methods reduce appointment no-shows but introduce completion and environment problems. Excessive reminders exert pressure, while overbooking wastes participants’ time. Do not exclude high-no-show groups before examining whether the process is inaccessible.
Related
- Same group: Q1.11.1 Quotas cover target segments · Q1.11.2 Existing-user databases exclude prospects · Q1.11.4 Strict screening lengthens recruitment
- Adjacent: Q1.05 Participant recruitment · Q1.16 Time and budget constraints
- Search terms:
participant no-show·standby recruitment·over-recruitment