[EM] Why I prefer ranked-choice voting to approval voting

[Jeff O'Neill]

I recently wrote a blog post explaining why I prefer ranked-choice voting
(i.e., IRV or alternative vote) to approval voting.  It is a quite
different kind of argument than most of the posts here because it is a
policy argument rather than a mathematical one.  Nevertheless, I thought
people here might find it interesting.  I'd love to hear your comments and
any counterarguments as well.

I've copied the post below and you can also find it here:
    http://blog.opavote.com/2016/10/why-i-prefer-ranked-
choice-voting-to.html

Why I prefer ranked-choice voting to approval voting
<https://3.bp.blogspot.com/-zufbCki-BVo/V_o1-OKl27I/AAAAAAAAASM/vrix1OAitpsQ4MhGoPunWk38sNcWu-qPwCLcB/s1600/rcv%2Bballot.png>
Voting is not an easy task for a voter.  I don't mean taking time off work,
getting to the polls, and waiting in line, etc.  I mean, when you are
standing there in the ballot box, you have to decide what vote you want to
cast given the options presented to you.  For example, a Jill Stein
supporter may be torn between supporting her favorite candidate and voting
for a candidate who has a better chance of winning the election.  I'll
refer to this as the *cognitive burden* of expressing your vote.

In this post, I'll address the cognitive burden of three different types of
voting:

   1. Plurality voting (i.e., selecting one candidate)
   2. Approval Voting
   3. Ranked-choice voting

OpaVote <http://www.opavote.com/> supports all three of these voting
methods if you want to try them out yourself.
Plurality Voting
Plurality voting is very simple, a voter simply picks one candidate.  There
is, however, a cognitive burden when there are more than two candidates.  A
voter presumably wants her vote to matter.  Accordingly, a voter should not
necessarily select her favorite candidate, but instead select her favorite
candidate who has a reasonable chance of being elected.

Consider the current U.S. Presidential election.  I'm a big supporter of
the Green Party, but Jill Stein is not going to win the election.  I'd like
to vote for the Green Party, but instead I'll vote for Hillary because that
is the best way for my vote to make a difference.  Others will vote for the
Green Party out of principle.

Where there are more viable candidates, the cognitive burden is much
higher.  The French 2012 elections for President had ten candidates in the
first round.  A voter thus needed to consider which candidates had a chance
of winning, and then select her favorite among those who had a chance of
winning.
Approval Voting
With approval voting, a voter has the option to approve as many candidates
as they like. The candidate with the most approvals is the winner. For
someone whose first choice is Jill, the voter may, for example, approve of
Jill and Hillary and not approve Donald and Gary.

Approval voting, like plurality voting, is very simple in practice.  A
voter just selects one or more candidates.  But Approval voting suffers
from similar cognitive burdens as plurality voting.  How do you draw the
line between candidates you approve and candidates you don't approve?

Consider a voter whose true preferences are:

   1. Jill Stein
   2. Hillary Clinton
   3. Gary Johnson
   4. Donald Trump

Clearly, this voter will approve Jill and will not approve Donald, but what
should she do with the other two candidates?  Should she also approve
Hillary?  Giving Hillary an approval may help Hillary beat Jill, but she
would certainly prefer Hillary to Gary or Donald.  Similarly, this voter
may not like Gary, but she may dislike Donald so much that it is worthwhile
to approve Gary to minimize the chance that Donald is elected.

Phew... that is a lot of thinking to do.  It would be even harder if Jill
and Gary had better chances of being elected.

In sum, approving any candidates other than your favorite can hurt your
favorite. Not approving candidates can help your least favorite get
elected.  Approval voting thus creates a significant cognitive burden for
voters.
Ranked-Choice Voting
With ranked-choice voting, a voter ranks the candidates in order of
preference, similar to the picture above.  In my view, this has the least
cognitive burden among the three methods discussed here.  It is easy for a
voter to pick her favorite candidate, pick her second favorite, and so on.
This kind of ballot has low cognitive burden because a voter doesn't have
to consider which candidates are viable.

But, you may ask, "Doesn't a voter have to think about whether their second
and later preferences might hurt their first preference? For example,
should a Jill Stein supporter not rank Hillary second because it might help
Hillary beat Jill?"

The great think about ranked-choice voting is that the answer to this
question is a clear and resoundingNO!!! Your second and later choices
cannot harm your first choice! Your second preference is only ever
considered at all if your first preference has definitively lost. Voting
geeks cause this the later-no-harm criterion
<https://en.wikipedia.org/wiki/Later-no-harm_criterion>.

Voters thus need to be educated that later choices do not hurt earlier
choices so that voters are encouraged to rank as many candidates as
possible.  The more candidates a voter ranks, the greater influence the
voter has in the outcome of the election.

Accordingly, ranked-choice voting has the lowest cognitive burden.  A voter
simply needs to select their first choice, second choice, and so forth.
The voter does not need to consider which candidates are viable.

(For voting geeks who are leaping out of their seats to make points about
other voting systems criteria
<https://en.wikipedia.org/wiki/Category:Voting_system_criteria>, please
keep reading.)
Other Stuff...
In my view, it is extremely important to make it as easy as possible for
voters to vote, and, for the reasons described above, ranked-choice voting
does this better than both plurality and approval voting.

I want to briefly address another form of ranked voting called Condorcet
voting.  Condorcet voting also uses a ranked ballot, but the votes are
counted in a different way.  Condorcet voting doesn't satisfy the
later-no-harm criterion mentioned above, so it is possible that your second
and later choices could hurt your first choices.  The possibility, however,
that your second and later choices hurt your first choice is so small that,
for practical purposes, a voter to cannot take this into account, and thus
Condorcet voting has the same cognitive burden as ranked-choice voting.
While Condorcet voting is a great voting method, I still prefer
ranked-choice voting for public elections, and I'll address that in a
future blog post.

Another point to mention is that detractors of ranked-choice voting
complain that ranked-choice voting does not satisfy other voting systems
criteria, such as the monotonicity criterion
<https://en.wikipedia.org/wiki/Monotonicity_criterion>.  While this is
certainly true, for practical purposes, a voter cannot take the
monotonicity criterion into account when casting a vote.  It is just far
too complicated and you would need to know how everyone else is going to
vote.  The non-monotonicity of ranked-choice voting thus doesn't create a
cognitive burden.

Please let me know what you think, especially if you disagree.  I am happy
to post any well-reasoned dissent as comments or even give you the
opportunity to write your own blog post in rebuttal.
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