[EM] Approval-Strategy article at CES website
Juho Laatu
juho.laatu at gmail.com
Wed Nov 2 00:27:09 PDT 2016
Since educated approval voting is based on voting strategically (constructively, not maliciously) so that each voter tries to make a difference between some leading candidates, approval is more vulnerable to deceptive poll information than many other methods. Most voters are expected to vote strategically, and voting strategy will be derived from the available poll information. This strategic vulnerability applies to all polls, not only approval based polls.
On the other hand, although this vulnerability is very obvious and easy to apply in theory, I lean in the direction that in typical public elections strategic voting or strategic polling is not as big of a problem as one might think based on all the theoretical threat scenarios that are often discussed on this list. In all elections voters are likely to have also incentives to vote sincerely. In the mentioned example many B supporters may prefer to always approve B (also in the polls, not only in the actual election), and B supporters may not like approving also C in the polls, just to make it sure that B will be seen as a more popular candidate than C. Such tendencies to promote one's true favourite are related also to longer term developments, like keeping the number of votes up also in the following elections, and trying give as much positive push as possible to one's favourite party, current representatives and candidates even if they are not elected this time.
In real life TTR elections I have not observed any strong tendency to vote strategically at the first round. Some probably do vote strategically (one of the potential winners), but I guess it is more typical to just vote sincerely at the first round. Also in plurality elections, where strategic voting (of one of the two leading candidates) is often the only rational thing to do (from a theoretical point of view, if one's only goal is to win this particular election), many people still prefer to vote sincerely.
I would expect these sincere tendencies to apply also in approval elections. I.e. poll strategies would not be so strong that they would in practice lead to such rampant strategic behaviour in the polls that would have a serious impact on voting behaviour in the actual election. This applies even more to other relatively strategy free methods like Condorcet. I believe strategic voting would not be a problem in typical large public Condorcet elections. As I have mentioned a few times, I'm still waiting for someone to present some practical strategic voting guidance that could be applied in typical large public Condorcet elections. So far there is none. The existence of such valid strategic voting guidance depends also on how strongly the public approves / rejects strategic behaviour. But as said, I have not seen any good guidance that would work even in the most strategy friendly societies (where voters are happy to vote as told by the party strategists, and where people who do not use all available deceptive strategies are considered to be fools).
Juho
> On 02 Nov 2016, at 07:29, Michael Ossipoff <email9648742 at gmail.com> wrote:
>
> Ok, now I get it. Sure, that's the trouble with a pre-election poll to get information for voting. Deceptive insincere voting in the informational poll.
>
> That's a nagging doubt that probably is felt by everyone who suggests such pre-election informational polls.
>
> Thanks for bringing it up, and for clarifying it for me. I guess I missed the fact that you were talking about voting in the poll, and were discussing that deceptive poll-voting problem.
>
> On Tue, Nov 1, 2016 at 2:36 PM, Juho Laatu <juho.laatu at gmail.com <mailto:juho.laatu at gmail.com>> wrote:
>
>> On 01 Nov 2016, at 20:07, Michael Ossipoff <email9648742 at gmail.com <mailto:email9648742 at gmail.com>> wrote:
>>
>> B, as a 2nd choice, is at the borderline for approval, if the ">" have uniform magnitude for a particular faction.
>>
>
> I didn't assume anything very specific on the strength of the preferences in the sincere preferences. Unless the preference strengths are not totally radical (e.g. A>>>>>>>>>>>>B>C), B can be presented to the A supporters as an acceptable compromise candidate (when compared to the even worse C).
>> Approving hir or not is ok.
>>
>> I don't understand why you say that the B voters shouldn't approve B.
>>
>
> That's because A supporters should be made not to think that A and B are the leading candidates (as they are based on the sincere preferences), but that A and C are the leading candidates. If A supporters believe that A and C are the leading candidates (because of the strategic answers to the approval polls), some of them will approve also B, and with good probability that makes B the winner in the actual approval election (although A supporters have 51% majority and they would win if all of them simply bullet voted).
>
> The strategic plan is thus to hide the fact that in sincere opinions A and B are clearly the two leading candidates, and make the A supporters think that C is the second strongest candidate. That's why it makes sense not to approve one's favourite (B) in the approval polls. In the actual approval election B supporters will naturally all approve B.
>
> Juho
>
>> Michael Ossipoff
>>
>> On Nov 1, 2016 1:41 AM, "Juho Laatu" <juho.laatu at gmail.com <mailto:juho.laatu at gmail.com>> wrote:
>> I generated one example of strategic polling in approval elections with approval polls. No specific claims included. Just some food for your thoughts.
>>
>> Sincere preferences:
>>
>> 51: A>B>C
>> 49-c: B>C>A
>> c: C>B>A
>>
>> Approval poll results:
>>
>> 51-ab: {A}
>> ab: {A, B}
>> 49-c-x: {B, C} (strategic, see Note 1)
>> x: {C} (strategic and insincere, see Note 2)
>> c-cb: {C}
>> cb: {C, B}
>>
>> Note 1: All B supporters should approve C.
>> Note 2: Some B supporters should possibly not approve B. The intention is to keep the approval level of B (49-x+cb) high enough to make B look like a credible potential winner, but not as high as the approval level of C.
>>
>> Approval election results:
>>
>> 51-ab': {A}
>> ab': {A, B}
>> 49-c-bc: {B} (can be sincere)
>> bc: {B, C} (can be sincere)
>> c-cb': {C}
>> cb': {C, B}
>>
>> The strategic target of B supporters is to keep ab' and cb' as large as possible. The A supporters should approve also B as a lesser evil, to avoid C that seems to be very popular in the polls. The C supporters should approve also B as a lesser evil, to avoid A that seems to be very popular in the polls. Preferably ab' > ab, and cb' > cb.
>>
>> Most voters know that (in sincere preferences) B is some sort of a middle candidate between A and C.
>>
>> The best strategy (that we know but voters do not) of the A supporters would be to bullet vote, but some are likely to approve also B. The best strategy of the C supporters is to approve also B.
>>
>> This example says that approval polls may be used as a strategic tool, but I don't claim that approval polls would be worse (in approval elections) from this point of view than some other kind of polls.
>>
>> Juho
>>
>>
>>
>>> On 31 Oct 2016, at 01:11, Michael Ossipoff <email9648742 at gmail.com <mailto:email9648742 at gmail.com>> wrote:
>>>
>>> I'd like to comment on the article's strategy-suggestions. My comments will be interspersed below, demarkated above & below by a line of "&&&&&&&&&&&&&&&&"
>>>
>>> Introduction
>>>
>>> Tactical voting is when voters don’t cast purely honest ballots. While voters do this to a limited extent with approval voting (link is external) <http://approval-voting/>, the voting system still behaves remarkably well. For instance, voters can always express their honest favorite. And choosing just one candidate (bullet voting) only occurs in limited situations.
>>>
>>> Below is how approval voting strategy is likely to play out in a variety of common scenarios.
>>>
>>> Polling Assumption
>>>
>>> Since there’d be approval voting, there’d also be approval polling. It would make no sense to do polling framed in plurality when a different system is used; it would cease to be informative.
>>>
>>> Utility Assumption for Hypotheticals
>>>
>>> In these cases, let’s assume you hate Candidate Awful, are okay with Candidate Better, and love Candidate Classy. Let’s give them honest utility values (we’re rating them on a 0-10 scale):
>>>
>>> Awful: 0
>>> Better: 6
>>> Classy: 10
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> {Classy, Better} is a top-set, for you.
>>>
>>> You should approve both.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Polling Assumption
>>>
>>> Since there’d be approval voting, there’d also be approval polling. It would make no sense to do polling framed in plurality when a different system is used; it would cease to be informative.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> I don't agree. Either Brams or Fishburn or both wrote a paper suggesting an Approval-poll to provide tactical informaton. But such information could only come from a poll that asked people to indicate their favorite, or better-yet,their merit-ranking.
>>>
>>>
>>> The 2nd election, the binding one, is, by assumption, intended to benefit from the information from the first poll. But the 1st poll, if by Approval, is either 0-info, or has ulnreliable, guessed, predictive information. Then why would it indicate winnability in the 2nd vote?
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>> Approval Voting Example #1
>>>
>>> If approval polls:
>>>
>>> Awful: 50%
>>> Better: 50%
>>> Classy: 30%
>>> You want to vote for Better and Classy here.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Yes.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> You vote for Better because you want Better to beat Awful. Classy doesn’t have a shot, but you vote for her anyway to show your support and give her ideas more legitimacy.
>>>
>>> Approval Voting Example #2
>>>
>>> If approval polls:
>>>
>>> Awful: 50%
>>> Better: 50%
>>> Classy: 50%
>>> You still vote for Better and Classy.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Yes.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>>
>>>
>>> You don’t vote for Classy alone because you have a strong preference for Better against Awful. By only voting for Better or Classy, you risk Awful winning against both of them.
>>>
>>> Approval Voting Example #3
>>>
>>> If approval polls:
>>>
>>> Awful: 30%
>>> Better: 50%
>>> Classy: 50%
>>> You actually only vote for Classy here.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> I disagree.
>>>
>>>
>>>
>>> {Classy, Better} is your top-set. Electing from that set matters more than the matter of _which_ of is members wins.
>>>
>>> In fact, Awful's win-probability is 60% as great as those of Better & Classy. You don't want to take that chance of Awful outpolling Classy. So you approve your top-set.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> When Awful is enough out of the race, you can narrow your sights against Better and show your support for Classy.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> But Awful isn't fully out of the race.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> When exactly do you only vote for Classy? It depends on how far out of the competition Better is. And it depends on how much you dislike Better along with how likable Better is compared to Awful. If Awful and Better are similarly unlikable (you’re indifferent to which one wins), a voter may be more inclined to vote for Classy alone when she is closer to winning.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Of course. That's why you wouldn't approve Hillary if we were holding the November 2016 election by Approval.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> Approval Voting Example #4
>>>
>>> If approval polls:
>>>
>>> Awful: 50%
>>> Better: 30%
>>> Classy: 50%
>>> Again, your only vote is for Classy here.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Disagree.
>>>
>>> Awful has a 50% chance of outpolling Classy, and, even if Better's win-probability is slightly less than that of Awful & Classy, you should still approve (only) your entire top-set, which is {Classy, Better}.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> It’s not Better that’s giving competition to Awful anymore; it’s Classy competing against Awful. Whether you include Better in the vote would depend on how much you actually supported Better's views. Like in the first example where Classy had 30% and was a token vote, support for Better in this case is also a token vote because it likely won’t change the outcome. So, if you wanted to give support for Better because of some view he had that you liked, then you could get away with supporting him and Classy.
>>>
>>> [...]
>>> Conclusion
>>>
>>> These examples remove the argument that approval voting regresses to plurality voting (via bullet voting).
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Of course.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> There are numerous scenarios (as shown above) when bullet voting simply makes no strategic sense. But notice that when you do only vote for one candidate, it’s done in a way that’s not damaging to the outcome. Also, factoring in who is likely to win is something we do anyway when considering what to do under plurality voting. But with approval voting, we just have more options on what we can do with that information. Also note that it was always to your advantage to vote your favorite. That will ALWAYS be true with approval voting.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Disregard who you think is likely to win. Nearly everyone's "information" about that comes from disinformational, wealthy-agenda media, and should be completely disregarded.
>>>
>>> Though honest Internet polls give us a hint about who's the CWs (Jill Stein), for nearly everyone, it's a 0-info election. Anyway, as i've mentioned elsewhere, in our distorted electoral-system, voters who want something better instead of the Republocrat status-quo have a top-set & a bottom-set. When you do, you should approve (only) your top-set.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> Also, when there are more candidates, there are more variations on what to do. Though the concepts are the same. Expectantly, with more candidates, voters will also approve of more candidates on average. There may also be cross-support from multiple independents/third parties that share certain views.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Yes.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> Finally, even with “tactical” voting, approval voting will nearly always choose the candidate that can beat everyone in a head-to-head race. This is called a Condorcet winner. Approval voting does not achieve this flawlessly, but it does an excellent job nonetheless. It is also argued that when approval voting doesn’t select the Condorcet winner, it does so for good reason.
>>>
>>>
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>> Yes.
>>>
>>> &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
>>>
>>>
>>>
>>> More on this topic here.
>>>
>>> Topic:
>>> Tactical Voting <https://electology.org/topic/tactical-voting>
>>> ----
>>> Election-Methods mailing list - see http://electorama.com/em <http://electorama.com/em> for list info
>>
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