Voters in the largest counties in 10 key swing states may experience problems on Election Day because of insufficient preparation and inadequate poll booth and machine allocation plans, according to a report released today by FairVote, a nonpartisan advocacy group.

FairVote surveyed 26 election administrators in counties with over 500,000 residents in Colorado, Florida, Missouri, New Mexico, Michigan, Minnesota, Ohio, Pennsylvania, Virginia and Wisconsin. Researchers found that many counties do not have a standardized method for allocating poll booths, which may cause long lines on Election Day. Long lines are often caused by an inadequate number of poll booths and have plagued voters, particularly in lower-income neighborhoods, in the past several election cycles. The report shows that 10 of the counties surveyed were not preparing a written allocation plan before Election Day.

Though some officials explained how they would allocate resources, including using metrics such as the number of registered voters and previous turnout, not a single administrator surveyed could cite a specific scientific formula that they use for calculating the number of booths or machines needed.