A fair three-option referendum?

In general, a multi-option referendum requires preferential voting, and has the potential problem that there may be no clear winner.

However, when the options have a natural order, as in the case of the Scottish independence referendum (no change - more powers - independence), the situation is simpler. The options can be put using just two questions, and it is virtually impossible not to have a clear winner.

A recent YouGov poll (Feb 2012), which asked for voters' second as well as first preferences, confirms that voters do treat the three Scottish options as having a natural order, and thus confirm that there are three fair ways to hold a three-option referendum that are essentially equivalent, so that any one of them should yield a clear and fair result.