http://www.cs.uiowa.edu/~jones/voting/cogel/
Jones on Human Factors, Slide 5


Overvote rates for Global ES 2000 Accuvote users


Overvote rates for Optech users


What happened in Okaloosa, Manatee, Columbia and Escambia Counties?

These precinct count system can detect overvoted ballots, returning them to the voter for a second chance.

Columbia County -- pollworker actions defeated this feature!
Manatee County -- feature disabled in election setup!
Escambia County -- feature disabled in election setup!
Okaloosa County -- no information.

Orlando Sentinel, Orlando, May 6, 2001 "New system fumbles votes."

Moral: Let the Voter Fix the Error!