Single Transferable Vote and Instant Runoff Voting Software
OpenSTV is open-source software for implementing the single transferable vote and other voting methods such as instant runoff voting, Condorcet voting, and approval voting. OpenSTV is the only open-source software that implements the single transferable vote exactly as used by governments, including Scotland and the City of Cambridge, Massachusetts. These methods have been extensively verified against other software and/or actual election results.
Organizations can use OpenSTV to implement their own elections. First, the organization must adopt a voting method. Second, the organization must conduct the vote, and this will most likely be done with paper ballots. Third, the ballots must be entered into the OpenSTV program. Finally, you can use OpenSTV to count the votes and determine the winners of the election.
OpenSTV will run on MS Windows, Mac OS X, and Linux. To download OpenSTV to your computer, select the download link at the top of the page. Please send questions to the email list:
openstv at googlegroups.com
This website has been moved from SourceForge.net and is now hosted at its own address: www.OpenSTV.org. This will improve the performance of the site and provide us with more options for expanding content in the future.
Links to the old website should be automatically redirected to the new address, but please update your links/bookmarks to the new address because the automatic redirect is temporary.
Please let me know if you see anything with the new site that needs fixing.
This is a bugfix release to fix several bugs that appeared only in the Mac version of OpenSTV. This release is now available for download.
OpenSTV version 1.3 is now available. Select "Download OpenSTV" from the top of this page to get download links.
The most significant changes in this release are the following:
- Redesigned OpenSTV user interface: (1) User can only run an election from a saved ballot file (previously, you could use a ballot file in memory). (2) User can edit/create ballots in a separate Ballot File Editor window and save them to a file.
- Can save election results in HTML.
- More explanatory output for Condorcet elections.
- Added subclasses for different ballot types to make it easier to support new types.
- Changes under the hood that make OpenSTV easier to maintain.
There are three papers in Issue 26, now available at the Voting matters web site:
- A Buhagiar and J Lauri: STV in Malta: A crisis?
Anton Buhagiar and Josef Lauri consider a critical problem in the use of STV in Malta. Although STV is well established in Malta, the two-party system has the effect of expecting a higher degree of proportionality than STV can actually deliver. The authors propose a very interesting solution to this problem. - Brian Wichmann: Review — Mathematics and Democracy.
Brian Wichmann has been compiling ballot data from actual elections that use ranked ballots and created a database of information about the elections called STVDB. For several years, information about STVDB has been available on this website.
Now, a subset of the ballot data is available for download. This subset is called "full disclosure elections" or "F series" because the ballots are available to the public. The F series includes complete ballot information from government elections in several countries.
Download the F series here.
