manipulation and DPP telephone surveys

Right now there is a controversy stewing over the DPP’s telephone polls for the presidential primary.  It seems that some people (and most people are pointing at Tsai Ing-wen’s supporters) are telling their supporters to only support Tsai.  Other people seem to think that this is a betrayal of democratic ideals.  I think there are (at least) two ways to think about this.

But first, let’s look at the rules.  According to the DPP rules, presidential nomination polls must compare the DPP contestants to the KMT candidate, not to each other.  So each respondent is asked for his or her preference on Su vs. Ma, Tsai vs. Ma, and Hsu vs. Ma.  The respondents are not asked which of the three DPP contestants they like the best.  If only one DPP contestant beats Ma, that person wins the nomination.  If more than one beats Ma or if no one beats Ma, then the person with the highest percentage of supporters wins.  If there are two people tied, then the person with the largest advantage (or smallest deficit) over Ma wins.  However, ties are extremely unlikely since they will figure each person’s support out to four decimal places.

Let’s think about this from a DPP supporter’s point of view.  You prefer Su to Ma, and you prefer Tsai to Ma.  Essentially, your response has no impact at all on the result of the nomination contest because you have raised both candidates’ support by an equal amount.  However, what if you strongly prefer one to the other?  Without loss of generality, let’s suppose you strongly prefer Tsai to Su, but you also prefer Su to Ma.  The only way you can help Tsai to win the nomination is to not express support for Su.  Is this unethical?  I don’t think so.  Every election has strategic voting, and this is just another form of strategic voting.  Moreover, these strategic voters don’t have to actually support Ma.  They merely decline to answer the Ma vs. Su question.  This is sufficient to make their preferred outcome more likely.

From the DPP’s point of view, things are a bit murkier.  The DPP rules are set up to privilege moderate swing voters, not their core party supporters.  That is, the DPP made a strategic choice to let swing voters choose their party nominee because that should maximize their chances of winning the general election.  However, their core supporters might not appreciate effectively being told that they don’t matter, and those supporters might respond strategically, as described above, in an effort to play a more decisive role in the nomination process.  So party supporters are effectively subverting the party’s strategic decision to marginalize them.  This does not seem surprising to me.  Why should the people who care most passionately about the DPP not be intensely interested in who it nominates?  I think the DPP rules create incentives that most supporters should not be terribly happy with.

There is something else going on that I find much more interesting.  One DPP member is accusing another of instructing supporters not only to answer that they only support Tsai, but also to misrepresent their age.  Why would you want to misrepresent your age?  This has to do with survey methodology.  Your goal is to infer from the survey respondents what the general population looks like.  Unfortunately, your survey sample (the people you actually interview) rarely looks exactly like the general population.  On some variables, such as age, sex, and geographical distribution, we have very good statistics about what the population looks like.  So we have a pretty good idea if there are too many men or too many senior citizens in the sample.  The usual way to deal with this is to weight the sample.  Suppose people 60 and over are 10% of the total population and you interview 1000 people.  Your sample should have 100 respondents aged 60 and up.  However, suppose you actually only interview 80 such people.  The idea behind weighting is to inflate these 80 people so that they represent the 100 people you should have.  So you multiply each of them by 1.25.  Likewise, if you are supposed to have 200 people aged 30-40 and your sample actually includes 250 such people.  You would multiply each of them by 0.8.  So the devious strategy is to lie about you age and put yourself into one of the chronically underrepresented categories (which if memory serves me correctly are almost always 20-30 and 60+) so that your answer gets inflated, not deflated.

Well, now this is blatant manipulation.  However, there really isn’t much the DPP can do about it.  Once the public learns this trick, the only thing the DPP can do is to stop weighting, which makes the overall results less accurate.  Eventually, I wonder if this (as well as the feeling that strategic voting is immoral or otherwise undesirable) won’t be the eventual catalysts for the DPP (and maybe the KMT) to move away from telephone surveys.

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2 Responses to “manipulation and DPP telephone surveys”

  1. Echo Says:

    Agree with you, man.

    In fact, respondents trying to “manipulate” the polls come from all sides. Blue supporters do that, green supporters do that, too. But it is rare that the party launch a “movement” to teach people to do that. In this case, the KMT allegedly (by at least two magazines) told her supporters to “not choose Ma but choose Su” when asked “Su vs Ma”. The green supporters (not by the party itself) asked their supporters to answer “Tsai only” when they were ask “Su v Ma” or “Hsu v Ma.” Some go to the extreme to suggest voting for Ma in those two questions.

    So, now, we have a campaign that the blue camp asks their supporters to vote for the green, and the green camp asks their voters to vote for the blue. What a mess !

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