In a Taipei mayoral survey conducted from September 16 to 18, the Dai Li-an poll put Kuomintang incumbent Chiang Wan-an at 41.7 percent support and the Democratic Progressive Party's Puma Shen at 40.5 percent, a gap of just 1.2 percentage points.

Perceptions of who will win told a different story: 57.8 percent of respondents expected Chiang to prevail, against 21.3 percent for Shen, leaving a wide gap between support and expectation.

Cross-tabulation showed a clear age divide. Shen led among every age group from the twenties through the forties, while Chiang led among every group aged fifty and above.

An earlier survey in May had put Chiang at 58 percent and Shen at 30, a 28-point gap. The margin has narrowed sharply in four months. Chiang's campaign is reported to say its internal polling still shows a double-digit lead.

Minimum Caution in Reading Polls

Sampling methods, question wording and field periods differ from one pollster to another. The mix of landline and mobile respondents, and how undecided voters are handled, can change results. Comparing numbers across houses directly calls for care.

A gap between expected winner and stated support is also common. At the ballot box such perceptions sometimes produce strategic voting and sometimes rally a candidate's base instead. Which way it works shows only as election day nears.

Taipei's Overseas Chinese and the Ballot

Taipei is a city with dense links to Chinese communities abroad. Education, visas, investment and cultural exchange sit where city and central government policy overlap. For Chinese residents in Korea who hold Republic of China nationality, this election is a matter of an actual vote.