Recruiting respondents
One response per device
An optional per-study switch that stops the same browser from responding twice.
Turn on Limit to one response per device on the Recruit tab and a browser that has completed the study sees "You've already done this one" instead of the questions. The check uses a marker saved in the respondent's browser.
This is a deterrent, not identity verification. Clearing browser data or switching devices allows another response. For controlled panels, send individual links and track refs.
Test drive links ignore the limit, so your own team can rehearse repeatedly.