to send a census taker to your door. >> reporter: it helps determine everything from congressional representation to where more than $400 billion in federal funding is directed each year. the lingering question is just how much does that need to cost taxpayers? kate bolduan, cnn, washington. >> we still have many questions about why the census costs so much and we know many of you do now. so we invited stephen buckman to help explain some of these expenses. thanks for joining us. this letter. i got one. a lot of people got one. it went out last week. saying the census form was coming. a lot of people think it was a waste of money just to say it is coming. $85 million. what do you say to that? >> that's correct, don. there's a lot of scientific research and doing survey work that shows that if you send an advance letter or a trigger to someone saying that you're going to send them something in a week, that they'll actually have