OpenTally

OpenTally is an application for counting various preferential voting elections, with an academic focus, and emphasis on configurability.

OpenTally may be used in a number of different ways:

• as an online web application, no installation or special software required
• as a standalone command line application
• as a Rust library within another application

Features

OpenTally accepts data in the BLT file format, and can count votes using:

• weighted inclusive Gregory STV (e.g. Scottish STV)
• unweighted inclusive Gregory STV (e.g. Australian Senate STV)
• exclusive Gregory STV (e.g. PRSA 1977 and ERS97)
• Meek STV – with tree-packed ballots for efficient computation
• Wright STV

OpenTally is highly customisable, including options for:

• different quotas and quota rules (e.g. exact Droop, Hare)
• calculations using fixed-point arithmetic, guarded fixed-point (quasi-exact) or exact rational numbers
• different tie breaking rules (backwards, random, manual) with auditable deterministic random number generation
• multiple constraints (e.g. affirmative action rules)

Online usage

After preparing the BLT file, open the web UI. Select the BLT file, and click Count. OpenTally will count the election and display the results in a count sheet.

By clicking Show advanced options, you can customise the options used for the count. A detailed explanation of the various options can be found here.

Once the count is complete, you can click Print result to generate a printable result report.

Command line usage

OpenTally may also be invoked as a command line application. Run ./opentally --help to view help.

For example, run ./opentally stv path/to/blt_file.blt --ties backwards random --random-seed foobar.