Our study is using a chain referral system where the condition of the referrer (participant A) dictates the condition that the referee (Participant
is assigned to. So if Participant A is randomized to control, they get a unique ID number which includes indications of their condition. They will also, separately receive ‘coupon or referral codes’ to share with their friends. The friends can enter the code when they take the eligibility survey. When they enter the code, this will tell the system to assign them to the same condition as their friend. They will then be assigned an ID and auto-redirected to download the app assigned to that condition. The assignment of condition (whether that is randomization for those without a referral code, or condition assignment based on a referral code) needs to happen between the time that they assent to participate and when they complete the survey and be dependent upon the referral code they entered. How do I do this?? Any thoughts on how to do this are appreciated.