From the introduction:
Voter registration lists, also called voter rolls, are the gateway to voting. A citizen typically cannot cast a vote that will count unless her name appears on the voter registration rolls. Yet state and local officials regularly remove–or “purge”–citizens from voter rolls. In fact, thirty-nine states and the District of Columbia reported purging more than 13 million voters from registration rolls between 2004 and 2006. Purges, if done properly, are an important way to ensure that voter rolls are dependable, accurate, and up-to-date. Precise and carefully conducted purges can remove duplicate names, and people who have moved, died, or are otherwise ineligible.
Far too frequently, however, eligible, registered citizens show up to vote and discover their names have been removed from the voter lists. States maintain voter rolls in an inconsistent and unaccountable manner. Officials strike voters from the rolls through a process that is shrouded in secrecy, prone to error, and vulnerable to manipulation.
After a systematic examination of the purging activities of 12 states, the authors found four practices undermining voter roll maintenance:
• Purges rely on error-ridden lists
• Voters are purged secretly and without notice
• Bad “matching” criteria leaves voters vulnerable to manipulated purges
• Insufficient oversight leaves voters vulnerable to manipulated purges