It's a scam!! Promised $100, spent 15 minutes asking questions, then at the end said I qualify, but my group is full. They just got 15 minutes of my time for free - never again.
Absolutely not a scam. My husband and I have done several studies though them and have always been paid. Normally $100 or more. You don't get paid for a screener, you only get paid if you qualify and you do an online study that is normally and hour or more. I am sure no one promised them $100 just to talk for 15 minutes. They told them that it was if they qualified and did the actual study. They will only call you if you have signed up with them at some point. If you do get a call from them and no longer want to be in the system, just tell them.