California: Mail-in-ballot rejections analyzed in study | UC Davis News Service
Voting by mail surpassed 50 percent of votes cast in a general election in California for the first time in 2012. A new study shows that nearly 69,000 mailed ballots, or about 1 percent, were not counted, and why they were rejected. The top three reasons mail-in ballots were rejected: not arriving on time, not being signed or because signatures could not be verified, according to the study to be released Sept. 29 by the California Civic Engagement Project at the University of California, Davis, Center for Regional Change. "California has one of the highest mail ballot rejection rates in the country," said study author Mindy Romero, director of the California Civic Engagement Project. "Although 1 percent may not seem very high, that's tens of thousands of people whose votes were not counted. And these votes could make the difference in close elections."

