Michael J. Hamner and his colleagues just published a paper in the current issue of Political Research Quarterly, “The Impact of Changing Voting Systems on Residual Votes.” Here is the abstract from their study:

Problems in the 2000 presidential election, especially in Florida, initiated a large-scale shift toward new voting technology. Using cross-sectional and longitudinal data, we report on the effects of changes in voting systems in Florida and Michigan. The variety of initial conditions and the numerous changes make these excellent case studies. We find that reforms succeeded in reducing the residual vote. Every change from old to new technology resulted in a decline in residual votes that was significantly greater than in areas that did not change voting equipment. The percentage of residual votes in the 2004 presidential race in localities that changed voting systems was well under 1 percent, representing a 90 percent reduction in error in Florida and a 35 percent reduction in Michigan. We run these analyses separately for undervotes and overvotes. Using ecological-inference techniques, we investigate the persistence of residual votes when technology changed and find very little persistence.