Editing Voting machine (section)

===Optical scanning===
{{main|Optical scan voting system}}
{{further|Vote counting#Optical scan counting|Electronic voting#Paper-based electronic voting system|Electronic voting in the United States#Optical scan counting}}
[[File:2018 Ballots being counted in Santa Clara County.webm|thumb|Counting ballots by an optical scanner, San Jose, California, 2018]]

In an [[optical scan voting system]], or marksense, each voter's choices are marked on one or more pieces of paper, which then go through a scanner. The scanner creates an electronic image of each ballot, interprets it, creates a tally for each candidate, and usually stores the image for later review.

The voter may mark the paper directly, usually in a specific location for each candidate. Or the voter may select choices on an electronic screen, which then prints the chosen names, and a bar code or QR code summarizing all choices, on a sheet of paper to put in the scanner.<ref name="vv-bmd">{{Cite web |url=https://www.verifiedvoting.org/ballot-marking-devices/ |title=Ballot Marking Devices |website=Verified Voting |language=en-US |access-date=February 28, 2020 |archive-date=August 5, 2020 |archive-url=https://web.archive.org/web/20200805185249/https://www.verifiedvoting.org/ballot-marking-devices/ |url-status=dead }}</ref>

Hundreds of [[Electronic voting in the United States#Errors in optical scans|errors in optical scan systems]] have been found, from feeding ballots upside down, multiple ballots pulled through at once in central counts, paper jams, broken, blocked or overheated sensors which misinterpret some or many ballots, printing which does not align with the programming, programming errors, and loss of files.<ref name="bren10">{{Cite web |last=Norden |first=Lawrence |date=September 16, 2010 |title=Voting system failures: a database solution |url=https://www.brennancenter.org/sites/default/files/2019-08/Report_Voting_Machine_Failures_Database-Solution.pdf |access-date=July 7, 2020 |website=Brennan Center, NYU |archive-date=November 26, 2020 |archive-url=https://web.archive.org/web/20201126221213/https://www.brennancenter.org/sites/default/files/2019-08/Report_Voting_Machine_Failures_Database-Solution.pdf |url-status=live }}</ref>