End-to-end verifiability

There are many ways an election can go wrong or be suspect. Perhaps ballots were lost—and known to be lost. Perhaps a memory card failed—and was known to have failed. Perhaps more votes were reported than there were voters. Perhaps the announced outcome is correct but the evidence supporting it is incomplete or unconvincing. Perhaps some people claim to have observed irregularities. An election might appear outwardly to have been conducted properly but have an inaccurate outcome due to undetected errors or fraud.