Cambridge held its STV elections for city council and school committee last night, and since I live nearby, I decided to stop by and watch how they count the votes. Cambridge has been doing STV elections since 1941, and it shows by how organized they are. Here is my understanding of how the vote counting worked.

Cambridge uses ballots where the voters fill in bubbles with a pen to rank the candidates. Here is an example of this year's ballot.

At each precinct, the marked ballots are fed through an older-model Diebold Accuvote scanner. The scanner feeds the ballots into the large black boxes you can see in the picture. The ballots that do not scan correctly are fed into the blue boxes (now placed on top of the black boxes) so that they can be examined by hand. After the polls close, these boxes and the scanners are transferred to the central counting facility.

At the central counting facility, election officials remove the memory cards from the Accuvote scanners, and the information is transferred to a computer. Note that the memory cards do not contain all of the ballots. Other ballots must be dealt with separately, for example, ballots with write-in candidates and ballots that were rejected by the scanner.

A preliminary count is then performed using the ballots taken from the memory cards and using the Choice Plus Pro software. It is interesting that they perform the count with Choice Plus Pro on two separate computers to have an "independent" count. At some point, I will suggest that Cambridge use OpenSTV as an independent count.

Today, Cambridge is processing ballots with write-in candidates and those that were rejected by the scanner. I believe another preliminary count will be performed after this is done. Cambridge delays the official count until November 13, to give plenty of time for absentee ballots to be received. Absentee ballots must be mailed by election day, but for people living overseas, it could take some time for them to reach Cambridge.

This year's count is more difficult than most because there were many more write-in votes than usual. An incumbent candidate, Marjorie Decker, failed to get her name on the ballot, and she ran a write-in campaign.