Sorry to ruin your day but the national immunization survey is exempt from the national do not call list do to the fact it is a federal government agency the CDC can call you anytime it is a federal agency sorry for the bad news.
If it IS the CDC, as for the name of the principal investigator. Also remind the caller that research ethics requires informed consent, and it is every respondent's RIGHT to decline to participate AT ANY TIME. Harassment after that, well.. that no good either. If there is a legit survey, this particular recruited is in violation. He even had the nerve to insist on a justification from me as to why I declined! I hope he calls me again.
This is not a scam. The CDC is doing a survey about special needs children, not steal your money. If you don't have special needs children under 18 in your household, you can just be polite, tell them that, and you won't be called again. The do-not-call registry is for commercial telemarketers only.
Called my cell numerous times never leave message I don't want them calling, but I never answer the phone, either, so they are just wasting their time and money.