How much do Diary Studies cost

Diary studies span multiple sessions, so your cost estimate is built session-by-session rather than as one flat number. This article walks you through how that estimate is calculated, what's in the per-session breakdown, and how per-study and completion bonuses work.

How is my diary study's cost estimated?

On the Recruitment tab of your diary study project, you'll see a collapsed summary showing your total number of sessions and the total estimated cost across all of them — something like "4 sessions · $186.00." Click the dropdown to expand the summary into a per-session breakdown, showing the estimated cost for each individual session.

Outset's estimate assumes every recruited participant completes every session — it doesn't attempt to predict drop-off. That means the total you see is the maximum possible cost for your study as configured. In practice, diary studies almost always see some drop-off between sessions, so your actual final cost will typically come in at or below the estimate.

See our article on setting your initial participant count and planning for expected drop-off between sessions.

What's included in each session's cost breakdown?

When you expand a session's row, you'll see:

• Participants — the number of participants counted toward that session's cost (this uses your initial participant count for every session, since the estimate doesn't model drop-off)

• Incentive — the base payment per participant for completing that session

• Platform fee — Outset's per-participant fee for that session

• Per-study bonus — any additional bonus configured for completing that individual session (see below)

• Session subtotal — the total estimated cost for that session, combining the above

Please note: this is a maximum estimate. Because it assumes no drop-off, your actual cost will typically be lower — final billing is based on how many participants actually complete each session.

What's the difference between a per-study bonus and a completion bonus?

Diary studies support two separate bonus types, and they're calculated differently:

• Per-study bonus — an extra amount paid to a participant for completing an individual session. Outset defaults this to half the base incentive of your longest session.

• Completion bonus — a one-time bonus paid when a participant finishes the entire diary study (meeting whatever completion threshold you've set). Alternatively, you can choose to pay out a completion bonus on a different session. Outset defaults this to the full cost (incentive + platform fee) of your longest session.

For example, on a diary study where the longest session pays an $8 incentive plus a $4 platform fee:

• The default per-study bonus is $4.00 (half of the $8 incentive — not half of the $12 total cost)

• The default completion bonus is $12.00 (the full incentive + platform fee)

These defaults are meant to keep the per-session bonus tied to what the participant actually receives, while the completion bonus reflects the full value of a session. Both are fully editable — if you set your own amount, Outset won't overwrite it.

Hope this helps! If you have any further questions, please reach out to our team at support@outset.ai or via chat.