Don`t use opinion polls to unify candidate

Opinion polls could be used as a way to unify the presidential candidate of the opposition camp between the Democratic United Party`s presidential candidate Moon Jae-in and independent Ahn Cheol-soo. Used 10 years ago to unify then candidates Roh Moo-hyun and Chung Mong-joon, this method has supporters since it has a precedent and is thus easy to implement. But careful consideration is required about whether opinion polls are an appropriate method to unify a candidate who could become president.

In 2002, Roh and Chung agreed on the candidate unification method under the rule that the one who scored even 0.1-percentage point higher than his rival in opinion polls will become the candidate. Supporters of then ruling Grand National Party candidate Lee Hoi-chang were excluded from those polled, and the question was “Who do you prefer as the unified candidate, Roh or Chung?” That is, the polls were designed to measure public preference for who would be the unified candidate. If this method is used as it was in the past, more opinion polls would suggest higher approval ratings for Moon than Ahn as of the end of October.

But if the polls ask the question about the two candidates’ competitiveness in the presidential race, as in who would fare better against candidate Park Geun-hye of the ruling Saenuri Party, Ahn would top Moon. Depending on the method of the polls used, the nation’s 18th president, who will share good times and bad with the people over a five-year term, could change. Putting the Republic of Korea’s fate on opinion polls surveying merely several thousand people as the sample group can hardly be construed as complying with the spirit of election-based democracy.

More problematic is selecting the candidate who scores just 0.1 percentage point higher in opinion polls than the other. Statistically, an opinion poll with a sample of 2,000 people translates into a confidence level of 95 percent and a margin of error of plus or minus 2.5 percent. The margin of error makes it impossible to determine the winner and loser with a gap of up to 5 percent. For instance, if one candidate has an approval rate of 52.5 percent and his or her rival 47.5 percent, the gap between the two amounts to 5 percentage points. The statistical conclusion for this is that there is no winner or loser. As such, determining that the one who gains an advantage of 0.1 percentage point in approval ratings is the winner equals an unconditional and reckless interpretation. This also cannot exist from the perspective of election-based democracy and represents an exaggeration of public opinions in that it constitutes misguided random judgment about public opinions as if they have been confirmed. If opinion polls are used to unify the opposition`s candidate while the latest trends of approval ratings continue, the gap will remain within the margin of error. If the winner and loser are picked based on such results, exaggeration of public opinions is the likely result.

The opposition camp might think that even if public opinions were exaggerated, Roh Moo-hyun was elected in 2002 and thus such an exaggeration could recur this time. This would be neither new politics nor political reform but derision of the public. Ten years ago, leading polling agencies rejected conducting opinion surveys, saying that the method to field a single candidate based on opinion polls was wrong. As results, smaller pollsters conducted the polls. Even without these problems, if the Democratic United Party agreed on this method, it would be no different from denying the significance of its own intra-party convention conducted in the form of a public primary that involved a million people. More fundamentally, the party`s selection of its presidential candidate who was elected himself with an independent candidate will represent an act of self-denial that throws cold water on party politics.