Category: Ranked-choice voting

Notes on preferential voting in America, emphasizing developments from about 1990 to present.

Vote splitting

This construct has long been a feature of Approval Voting advocacy. It refers to the possibility that two or more likeminded candidates in a plurality election appeal to the same group of voters, thereby dividing that group’s support.

Advocates of Approval Voting (and derivative rules) naturally gravitate to this construct. It is intuitive. It seems like it happens often. And, on its face, it makes a great case for Approval Voting. Heck, you just vote for both candidates!

With the entry of “vote splitting” into high-profile RCV advocacy, it may be time to take a critical view.

Nagel has shown that, under Approval Voting, two candidates appealing to the same group of voters actually have an incentive to encourage vote-splitting. The reason is that each cares about winning.

I am told of similar results for the Alternative Vote (aka IRV/RCV).

What about vote-splitting where everyone thinks it happened? I am talking about prominent presidential elections with minor-party candidates. Two recent studies suggest relatively little vote-splitting in practice: one on Libertarians, then a second on Stein/Greens and Johnson/Libertarians alike.

To find that third-party voters don’t break reliably in either direction is not surprising. Typically, such candidacies reflect the activation of some alternative issue dimension (e.g., climate).

That issue may even be so important (to third-party voters) that they refuse to rank (or approve/score) putative lower choices. Hence the Australian solution: compulsory ranking.

My personal view is that “vote splitting” has become an indulgent kludge. The obvious solution to the purported problem is to unite behind a single candidate. But this just will not do for a certain kind of reformer (indulgent). And it is a kludge because the problem is not demonstrated (nay, demonstrable) empirically — at least without considerable data on the policy preferences of voters and candidates alike.

Yet we will continue to hear about “vote splitting” because, without it, the case for single-seat reform evaporates.

Warnings from the past

Many people, on studying the matter, have come to the same conclusion.

Gove (1894):

Another serious objection is that a heavy additional burden is imposed on the voter by requiring him to indicate several names in the order of his preference instead of indicating but one choice, as in the other systems. This burden the voter would be very loth to assume, since it is with difficulty that voters are induced to discharge the duties already imposed upon them.

Lien (1925):

While the Hare system is meticulously more accurate as a plan of propor­tional representation than the Free List system so widely used on the continent of Europe, it is certain that for the election of members of our state legislatures or of our Congress, the Free List plan (with its close approximation to complete proportional representation) would be much more in accord with our voting habits and consequently much more acceptable and intelligible to the voters.

Weeks (1937):

All states except Alabama and Oklahoma did not require the voter to register more than a first choice for any office. It seems to have been quite common in all the states indicated above that a great many voters failed to avail themselves of the privilege of registering second or more choices, which resulted in the practical restoration of the plurality system in many primary races. This failure was due to several causes: ignorance of the voter; his desire not to have his vote counted for any but his first choice; or his refusal to accept what was thought to be a complicated system, which, it was felt, could be easily corrupted or readily subject to mistakes in the count, or which seemed to provide for an unfair method of evaluating choices.

Gosnell (1939):

Under the list plan, the voters would have to choose only one candidate, the best man from the group which they favored most. The results of the election would be known shortly after the single-preference votes had been counted. It is urged that the proposed system would probably lessen constitutional difficulties, simplify the task of the voter, save the expense and delay of the Hare count, and give substantially the same results.

Further reading here. Sources here.

New York City is the largest rollout of ranked ballots in human history

More on it soon. For now, the data.

Jurisdictions not included are: other Progressive Era adoptions (hard to imagine those populations being bigger), U.S. adoptions since late April 2021 (ditto), adoptions for military/overseas voters (ditto and see link), and state/provincial/municipal adoptions in other countries (ditto).

For various reasons, population does not reflect the pool of eligible voters.