market research

Perhaps the organisation you work for could arrange appointments in advance with people who are willing to be interviewed.
I certainly wouldn't have someone in my house to do a survey without prior arrangement I'm afraid, but I did participate in something a few years ago (from the council I think) who had sent a letter about it, and booked a time.
I've also been to focus groups which were quite interesting.

I never answer surveys, whether on the phone or in person (although I am never rude). Why would I give personal information to a total stranger. Whilst I am sure your survey is above board there are those who attempt to get private information in order to steal identities.