Today, Dec 31, is the last day that polls can be published before the ten-day blackout period starts. A couple last polls straggled in this morning, so I can now present the final weighted poll chart for this year’s election. (For methodology, please refer to the original post.)
This is an astonishing chart. All year long, Tsai Ing-wen’s fortunes have steadily improved while Han’s continually eroded. There was no single event that suddenly transformed the election; it happened bit by bit. While there was no single day that felt completely different from the day before, the race at the end of the year is completely different from at the beginning of the year. My chart only goes back to May, when we started to get a steady enough flow of polls that I could put together a daily average. However, if you look at individual pollsters with longer data series, you can see that the race had already started to change by May. In February, Tsai was much further behind. Here are the data series for the two most reputable pollsters this year, TVBS and Formosa. TVBS has a consistent blue bias, while Formosa tilts a bit toward the green side. Both show the same basic picture: Han starts out with a big lead, which slowly turns into a big deficit. The “golden cross,” the point at which Tsai overtakes Han, is much earlier in the Formosa chart, but that is to be expected given the partisan skew of the two polls.