People say “yes” to cookie policies all the time. However, saying “yes” does not mean study participants are aware that their information can be used for advertising purposes. It may lead them to unexpectedly see targeted ads about the study or their health condition when they visit other websites.

Targeted advertisements could make participants feel embarassed, worried, and distrustful about who has access to their information. These negative feelings could cause a participant to stop contributing data and to withdraw from the study.

Instead of making participants accept all cookies, tell participants that their cookies might be capturing other sensitive data. Inform them about what types of cookies you are collecting for the study, what purpose they serve for the study, and if any 3rd-party will be involved in processing this data. Ask participants for explicit consent before using these cookies for targeted advertising, and always give them the option to opt out.

Consider educating your participants on how to turn off 3rd-party cookies to stop organizations from creating targeted ads based on their personal health information. Doing so can help set reasonable expectations about privacy, build trust, and increase the participant’s commitment to the study.