This report examines the use of voting equipment and the incidence of spoiled and unmarked ballots associated with that equipment. We call the rate of spoiled and unmarked ballots the residual vote rate. The residual vote rate is not a pure measure of voter error. If voting technologies are not producing voter mistakes or confusion, the residual vote rate should be unrelated to equipment. The study covers election results from over 2700 counties and municipalities in the 1988, 1992, 1996, and 2000 presidential elections.