The real reason why PPP's approval rating seemed to have gone up (credit to u/J_S_Han)
Credit to u/J_S_Han
https://reddit.com/r/korea/comments/1i368rp/presidential_security_guards_forced_to_sing_a/m7kmc6v/
The devil is in the details; here's the actual link to the Gallup poll in question, and here are the stats.
Out of 1,001 surveyed, for political affiliation 123 refused to respond or were politically apathetic, so realistically the poll only shows the opinion of 878 (1,001 - 123 = 878).
Of those 878, those who identify as conservatives were given a larger percentage than other groups, at 338. this represents 38.49% of the people polled.
278 of the 878 (31.66%) identified as moderate/neutral, and 262 of the 878 (29.84%) identified as liberal.
If I recall correctly, Gallup Korea rounds up the percentages for party approval rating, and given how close 38.49% is to 39%, PPP party supporters only included conservatives and virtually non of the moderates and liberals.
The liberals on the other hand got an approval rating of 36% despite representing 29.84% of the group surveyed, meaning they have a decent chunk of moderate voters.
South Korea political climate has been divided into roughly 33% liberal, 33% conservative, and 33% moderate/apathetic for the last 15 or 20 years, plus or minus a couple percentage points. This is the golden ratio you want to use when calculating how accurate polls are.
If one group surveyed gets a larger chunk of the audience, then it'll be lopsided in favor of that group.
TLDR: Gallup Korea poll is slightly skewed in favor of conservatives. Even then, the PPP party won 0 support from moderates/neutral, which means they're fucked in future elections.
In two party political elections, the goal is to win over the moderates and swing voters because they provide the decisive edge.