Pennsylvania’s voting machines go through several layers of testing – both on federal and state levels – to make sure the results they produce are accurate, writes Carter Walker for KYW Newsradio.

All voting machines are tested before every election to ensure they are working properly.

Each machine produces paper ballots that can be audited. This provides election officials with a way to verify the accuracy of the election results long after voting has concluded.

“This is the most important security feature that voting systems can have, is that there is a paper record of every single vote cast,” said Derek Tisler, an attorney with the Brennan Center for Justice’s Democracy Program.

Counties in Pennsylvania decide on which voting machines to purchase, with the oversight of Pennsylvania Department of State.

At this time, 70 percent of counties have voters mark a paper ballot by hand, which is then fed to a tabulator that scans, tallies, and stores the votes. Paper ballots are retained in case of an audit or recount.

The remaining 30 percent use machines where voters make their selections on a screen which then prints out a ballot.

Read more about voting machines at KYW Newsradio.