Interesting link about how Florida's Voter Registration File is skewed against African-Americans.
The February 15, 2005 Florida registration file includes the registered voter's race. The analysis was done both with missing apartment numbers and missing or erroneous zip codes. The voter registration file studied is dated February 15, 2005, the percentage of African-Americans is 11.8%, but the percentage of missing apartment numbers for African-Americans is 19.1%, and the percentage of missing or erroneous zip codes for African-Americans was 25.3%. The analysis was done as argument against any proposed all-mail balloting election in Florida.
ANALYSIS FOUND HERE:
http://elections.gmu.edu/McDonald_Florida_Voter_Registration_Memo.pdf