Prolific vs Optimal Workshop

From $6 per participant (indicative, plus platform fee)

From $199 per month (indicative, per user)

You set the incentive with a fair-pay minimum, plus a percentage service fee. Far cheaper than moderated-research platforms.

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

No subscription; pay per participant.

Free plan with limited participants per study.

Widely used

Prolific · since 2014

Established

Optimal Workshop · since 2008

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

• 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.

• 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.

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

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

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