Optimal Workshop vs Prolific

From $199 per month (billed annually, includes 5 launched studies)

From $8 per participant/hour minimum incentive, plus platform fee

Annual plans reduce the effective monthly rate substantially; recruitment is separate.

You set the incentive subject to a fair-pay floor of $8/hour ($12 recommended), then Prolific adds a platform fee — around 42.8% for commercial customers, 33.3% for academic and non-profit. Budget the fee: it is a large fraction, not a rounding error. Still far cheaper than moderated-research platforms.

Free plan with limited participants per study.

No subscription; pay per participant.

Established

Optimal Workshop · since 2008

Widely used

Prolific · since 2014

• The reference tool for card sorting and tree testing; the analysis visualisations are excellent.
• Tree testing validates navigation before any build effort is spent.
• Well-established methodology support and training material.

• Notably better data quality than generic survey panels.
• Fine-grained prescreening across hundreds of demographic attributes.
• No subscription — pay only for what you run.

• Narrow scope — it does not do usability testing of interfaces.
• Expensive per seat for occasional use.
• Interface is dated in places.

• Recruitment only; you supply the study and the tooling.
• Skewed towards students and younger, online-native participants.
• Not suited to recruiting senior enterprise decision-makers.

Teams restructuring navigation, taxonomy or content on a large site.

Survey-based and quantitative studies where data quality matters and budget is limited.