The graph derives from the 2008 Survey of the Performance of American Elections, which was conducted over the week after the November election and was designed by the Caltech/MIT Voting Technology Project. Some preliminary results are here, on which the graph is based. The graph basically presents the percentage of respondents who had no problems with a particular aspect of the voting experience.
I’m struck by a couple things. First, despite the attention frequently paid to problems using voting machines and long lines at polling places, these things were not major problems at all. Similarly, few absentee voters had problems receiving or filling out their ballots.
Second, there is a striking gap between the actual experience of voting — which, for most people, seemed to go smoothly — and their confidence that their ballot was counted. And there is a fascinating partisan dimension to voter confidence (see the results for graphs): Democrats who lived in states where Obama won were more confident that their vote was counted than were those who lived in states where he lost. Similarly, Republicans were more confident in states where McCain won.
A possible implication: no matter how much we do to improve the voting process, some voters — especially those in the partisan minority in a state — will always doubt that their vote was counted.
(Previous posts on this subject are here and here.)