Tracking: Run Multi-Wave Studies

Tracking re-invites the same respondents at different points in time so you can observe how an individual’s attitude, experience, or behavior changes.

Use it for product before/after studies, brand tracking, habit formation, and longitudinal academic research. If each wave may use a fresh sample, choose independent waves or launch separate ordinary distributions.

Current scope

Advanced tracking currently applies to standard survey panel distribution. AI interview samples do not yet support it.

Choose where the panel starts

Start with the current survey

The current survey becomes wave 1 and recruits a new panel. This is best for a multi-wave study designed from the beginning.

Continue a historical distribution

Choose one of your earlier panel tasks as wave 1. The current survey becomes wave 2 and re-invites distinct respondents whose historical completions were valid and not rejected in review.

The selector shows how many people can be re-invited and may include ordinary or existing tracking tasks. A task is eligible only when it:

• belongs to the current account;
• has actually been distributed and is not awaiting payment, refunded, stopped, or canceled;
• has at least one valid completer.

This supports studies that become longitudinal only after the first study has already finished.

Note

The displayed re-invitable count is an upper-bound reference. With “original respondents only,” the current-wave suggestion cannot exceed the historical valid-completer count.

Waves and cadence

Set 2–12 waves using:

• weekly;
• every two weeks;
• monthly;
• custom dates for every wave.

Custom dates must be filled and increase in order. The timeline previews the plan.

“Require my confirmation before each wave” is on by default. The publisher is notified before the planned time and confirms and pays before the wave opens. If it is off, already prepaid waves can open automatically on schedule.

Bind a survey to each wave

Reuse the current survey

Later waves use the current survey, ideal for repeated measurement. When continuing history, wave 1 keeps the historical survey and wave 2 onward uses the current one.

Use a different survey per wave

For a new project, wave 1 is fixed to the current survey. When continuing history, wave 1 is historical and wave 2 is current. Remaining waves can each select another published survey.

A later-wave survey may be left blank and assigned later. While the project runs, you can change the survey for any wave that has not started. Running or settled waves cannot be changed.

If a due wave still has no survey, invitations cannot be sent until one is assigned.

Work backward from the final target

The system estimates the current recruitment need from:

• final-wave target;
• expected retention per wave;
• remaining transitions.

For a new panel:

wave-1 suggestion = ceil(final target / retention rate ^ (wave count - 1))

For 200 completes in wave 3 at 60% retention:

Wave 1: 200 / 0.6² ≈ 556
Wave 2: 556 × 0.6 ≈ 333
Wave 3: 333 × 0.6 ≈ 200

When continuing history, wave 1 already exists, so the system estimates only from the current wave 2 to the final wave.

Retention can be set from 0.1% to 95%, and the final target and single-task limit are 9,999. A combination that requires more than 9,999 people blocks quoting and payment.

Planning note

Retention is an assumption, not a guarantee. Survey burden, spacing, incentives, and topic all affect returns. Repeated distribution commonly has roughly 30%–60% response loss, so leave a buffer.

Advanced settings

Incentives by wave

Set each wave from 1× to 5×. The recommended curve begins at 1× and compounds by about 20%, such as 1.0, 1.2, and 1.5.

The multiplier applies on both sides: the publisher pays more for that wave and respondents receive the same higher reward multiple.

What to do when retention is short

Independent waves are offered only for a new panel. If replenishment exceeds the amount prepaid for the wave, the publisher must make an additional payment.

Automatic reminders

Set 0–3 reminders per non-responder. The system uses currently available SMS, email, official-account, or app-push channels.

Respondent consent

Repeated contact requires clear disclosure of the wave count, time span, contact channels, and opt-out path. Include only respondents who agree to future invitations in longitudinal analysis.

Payment options

Pay for the current wave

• A new project pays for wave 1;
• A historical continuation treats history as completed and pays for the current wave 2;
• Every later wave is confirmed and paid before distribution starts.

Later-wave expected count first uses actual valid completions from the previous wave. When no actual data exists yet, estimates use the final target and retention rate.

Pay all waves upfront

The first order includes the current wave and estimated prepayments for all future waves. Future waves open automatically when due, without another payment confirmation.

Prepayment uses estimated counts; each wave is still settled independently on actual valid completes.

Billing and settlement

The task locks the current sample unit price at creation. Later waves reuse it and apply their incentive multiplier.

wave prepayment = expected count × locked unit price × wave multiplier
wave settlement = actual valid completes × locked unit price × wave multiplier
wave refund = max(0, prepayment - settlement)

• Excess prepayment returns to the original payment method;
• Settlement follows “refund the difference, do not collect extra” if actual completion exceeds the prepaid cap;
• Unopened and unpaid waves incur no cost;
• Canceling a running wave settles valid completes and refunds the unused prepayment;
• Canceling future waves after paying upfront processes the unexecuted amounts by wave.

See How Pricing Is Calculated for the full base, screening, quota, and tracking formula.

Wave status in task details

When the next wave opens, the previous one is settled. Re-invitations come from distinct previous-wave respondents with valid, non-rejected completions.

FAQ

Why is a historical task missing?

Check that it belongs to the current account, was actually distributed, and has at least one valid completer. Awaiting-payment, refunded, stopped, and canceled tasks are excluded.

Is the retention estimate guaranteed?

No. It is for recruitment and budget planning. Higher later-wave rewards, shorter intervals, reminders, or replenishment can reduce a shortfall.

Can I create the plan before later surveys are ready?

Yes. Choose different surveys per wave and leave future waves blank. Assign an owned, published survey before each wave starts.

Which strategy should I use to compare individuals?

Choose original respondents only. Replenishment and independent recruitment improve per-wave size but no longer represent exactly the same people.

Other names used in the industry

Professional participant platforms commonly call this a longitudinal study and each round a wave. “Panel” may mean either the source pool of respondents or the same fixed group followed over time; this page uses it in the second sense when discussing longitudinal analysis.

Related designs that are not identical

• Panel / fixed-sample study: follows the same respondents and is closest to Wejot’s default tracking mode;
• Repeated cross-sectional study: recruits a fresh sample each wave and corresponds to independent waves;
• Brand tracking: describes the research purpose and may use either a fixed panel or repeated cross-sections;
• Diary study / experience sampling: collects frequent in-the-moment records and is a related longitudinal method, but not synonymous with a standard multi-wave survey;
• Cohort study: follows a group defined by a shared characteristic and is often broader and longer than one survey project.