Schulze STV

Schulze STV is similar to CPO-STV in that it compares possible winning candidate pairs and selects the Condorcet winner.

It is named in analogy to the single transferable vote (STV), but only shares its aim of proportional representation, and is otherwise based on unrelated principles.

The system is based on Schulze's investigations into vote management and free riding.

Schulze STV is designed to be as resistant to free riding as possible, without giving up the Droop proportionality criterion.

If the Yellow Party's leaders instruct their supporters to choose Carter first (followed by Andrea), the balloting changes.

[citation needed] Schulze STV aims to have additional resistance to forms of tactical voting which are specific to single transferable voting methods, in particular a phenomenon that Schulze calls Hylland Free Riding.

As Schulze STV reduces to the Schulze method in single winner elections, it fails the participation criterion, the later-no-harm criterion and the later-no-help criterion, whereas traditional forms of STV (that reduce to IRV in single winner elections) fulfill later-no-help and later-no-harm.

The algorithm implementing Schulze STV requires exponentially many steps in the number of seats to be filled (roughly on the order of

steps when k out of m candidates are to be selected), making the computation difficult if this number is not very small.