The actual ballots are stored, a selective audit is done to verify the electronic count, and in the event that raises issues a full manual recount can be done.
The electronic voting system issues in the 2000 elections motivated the Help America Vote Act of 2002 under which voter-verified paper records for audit purpose required for all voting machines (this requirement became effective in 2006); effectively, “voting machines” add ballot marking machines that may also be involved in convenience tabulation, but are always audited against hand counts of paper ballots, which are the ultimate authority.
The electronic voting system issues in the 2000 elections motivated the Help America Vote Act of 2002 under which voter-verified paper records for audit purpose required for all voting machines (this requirement became effective in 2006); effectively, “voting machines” add ballot marking machines that may also be involved in convenience tabulation, but are always audited against hand counts of paper ballots, which are the ultimate authority.