Busan Mayoral Election Poll Analysis: Park Predicts "Golden Cross on 19th" vs. Jeon Cites "Gap Beyond Margin of Error"

Busan Mayoral Election Polls: Fluctuating Fortunes


"Gap Narrowing" vs "Regaining Momentum"


Different Results by Survey... Swing and Undecided Voters as Key Variables

As the June 3 Busan mayoral election approaches, a debate over "margins of error" has erupted.

Park Hyungjoon’s campaign, emphasizing that "the race is neck and neck within the margin of error," is even preparing based on its own analysis predicting that a golden cross will occur around the 19th. In contrast, Jeon Jaesoo’s camp asserts that "recent polls show the gap has widened beyond the margin of error," arguing that a reversal in trend is impossible.

As the election draws nearer, Park Hyungjoon’s campaign, which is closely pursuing Democratic Party candidate Jeon Jaesoo, is calculating the timing of a "trend reversal" based on its own analysis of the race and polling data.

With the competition between Democratic Party candidate Jeon Jaesoo and People Power Party candidate Park Hyungjoon intensifying recently, some polls indicate the two candidates are in a competitive structure within the margin of error. Other polls, however, show the gap outside the margin of error, cooling down the atmosphere.

According to Park’s campaign on May 15, its own analysis predicts that Park Hyungjoon of the People Power Party will overtake his rival within the margin of error as of the 19th.

A Park campaign representative explained that this prediction is based on the results of 10 polls conducted since April 13, when the gap between the two candidates was at 10 percentage points.

According to a poll conducted by Yeoronchosakkot from April 13 to 14 using ARS with 1,004 Busan residents aged 18 and older, Jeon received 48.7% support and Park 38.7%. The margin of error was plus or minus 3.1 percentage points at a 95% confidence level, with a response rate of 7.4%.

Subsequent polls showed Jeon’s support rate hovering around 50%, indicating the gap was widening.

The trend shifted in May. Park’s support rate surged past 40%. In a poll conducted by Hangil Research on May 1-2 among 1,013 respondents using 100% ARS, Jeon had 46.9% and Park had 40.7%, which was within the margin of error. The margin of error was plus or minus 3.1 percentage points at a 95% confidence level, and the response rate was 6.9%.

According to a poll by Gallup Korea on May 10-11 using wireless phone interviews with 801 respondents, 43% favored Jeon Jaesoo, while 41% favored People Power Party candidate Park Hyungjoon. This was the closest result among the polls. The margin of error was plus or minus 3.5 percentage points at a 95% confidence level, and the response rates were 6.9% and 14.7%, respectively.

Using April 29—the point when changes in support rates were detected—as a benchmark, Jeon’s support rate dropped from 49.8% to 43.0% by May 11. This is a daily average drop of -0.567 percentage points. Park’s support rate rose by 12.5 percentage points, or an average of 1.042 percentage points per day. At this rate, support rates would cross on the morning of the 12th. Experts commented, "We are now in a probabilistic domain where the rankings could flip every day."

However, while the gap narrowed to 6.2 percentage points in the May 1-2 Hangil Research poll, it widened again to 9.9 percentage points in the May 9-10 Researchwell poll. Given the occurrence of nonlinear fluctuations, a quadratic equation graph can be drawn.

Jeon’s trend forms a gentle U-shape or moves sideways, while Park’s trend is a sharp V-shape, with a steep decline in late April followed by a rapid rise in May.

Park’s campaign calculated that the χ value, where the two curves intersect in the quadratic function, is 35.8. Based on April 13, this means the crossover point in support rates would fall on May 19, 36 days later. They predict the trend reversal will occur on the 19th based on this analysis.

However, political circles offer differing interpretations of recent poll trends. The People Power Party side analyzes that Park’s support rate is on the rise, while the Democratic Party side believes Jeon’s lead remains intact. In fact, some recent polls claim the support gap has widened. This divergence in trend and race analysis between the two camps is a defining feature of this election.

Local political circles and polling experts have pointed out that poll results may differ depending on survey methodology or how candidates are named.

Whether the "dead cross" moment predicted by Park’s camp materializes or remains just talk within the campaign is drawing attention. Until the end of the race, the votes of undecided and moderate voters are expected to be key variables.

This content was produced with the assistance of AI translation services.