So the other day, we're getting ready to go somewhere, and a surveyor called to say our phone number had been randomly selected for the CDC's National Immunization Survey [NIS], did we have any children in the house?
When I asked how long it would take, though, the woman kept refusing to answer. She had her screening script, and was sticking with it. So I told her there's no way we'll participate without knowing how long it'll take, so she should just call us later.
Well, they called back this morning while I was out, and my wife did the survey. Turns out they're collecting anonymous, but detailed immunization information on kids 12-36 months old. So they want you to pull out your records of the kid's shots.
All in all, it took around 20 minutes on the phone. If your kid has had health issues, there might be 1-2 five-minute add-on sections, but that's about it. Also, they'll ask if they can contact your pediatrician to confirm the immunization records [using name and date of birth], but then they apparently strip the identifying info off the survey data as soon as it's confirmed. You can, of course, decline to give them actual identifying info. They also offer several ways to confirm their own identity and authenticity which, depending on your comfort/suspicion level, you may want to use.
And now you know.
National Immunization Survey [cdc.gov]