Changes

==Undercount and Overcount==

==Undercount and Overcount==

Statisticians now estimate that the 1990 Census missed about 4.7 million people who should have been counted.  They estimate that the 2000 Census missed 6.4 million people, and double counted 3.1 million others, for a net undercount of 3.3 million. For example, only 64% of the people return the mailed forms.  To reach the other 36% the Census tries multiple followup visits in person. These are very expensive, and even then many people refuse to answer the door. People who moved around are sometimes counted twice, as are some students and prisoners who can be counted at home and at their institutions. Children of divorced parents are often listed by both parents. Some households are so complicated or chaotic that the person filling out the forms is unclear who is living there today.<ref> See Freedman and Wachter (2004) pp. 6-8</ref>

Statisticians now estimate that the 1990 Census missed about 4.7 million people who should have been counted.  They estimate that the 2000 Census missed 6.4 million people, and double counted 3.1 million others, for a net undercount of 3.3 million. For example, only 64% of the people return the mailed forms.  To reach the other 36% the Census tries multiple followup visits in person. These are very expensive, and even then many people refuse to answer the door. It costs $100 million dollars to reach another 1% of the missing 36%. People who moved around are sometimes counted twice, as are some students and prisoners who can be counted at home and at their institutions. Children of divorced parents are often listed by both parents. Some households are so complicated or chaotic that the person filling out the forms is unclear who is living there today.<ref> See Freedman and Wachter (2004) pp. 6-8</ref>

==Further reading==

==Further reading==