Turnout was lower than many expected. The previous low for turnout in a presidential election was 74.4% (in 2012), but this time turnout dropped to 66.3%. Some drop was expected, since the presidential race was not close and because the election was scheduled so near to the Lunar New Year holiday and university students’ final exams. However, many people have also speculated that a disproportionate number of demoralized blue voters would stay at home. We’ll never have a definitive answer to whether this was the case because we don’t have exit polls. The post-election academic surveys will provide some evidence, but those won’t be release for several months.
In the meantime, we can look for crude patterns in the district-level turnout data. If the hypothesis is correct, we should probably see larger drops in turnout in blue districts than in green districts. I’m going to use the number of valid votes to calculate turnout. (The actual figure includes both valid and invalid votes. These numbers are now available on the CEC website, but I’m going to save time and just use valid votes. Arguably, valid votes are a better indicator, since many disgruntled blue voters may have cast invalid votes.) Overall, turnout in the 73 districts dropped from 74.0% to 65.2%, a drop of 9.2%. However, some dropped more. For example, Hsinchu County dropped 12.4% and New Taipei 9 dropped 12.0%. Some dropped less, such as Chiayi County 1 (6.0%) and Pingtung 2 (6.8%). Not coincidentally, Hsinchu County and New Taipei 9 are very blue, while Chiayi County 1 and Pingtung 2 are very green. Those examples are not misleading, though the pattern is not usually quite so stark. The correlation between the drop in turnout and Tsai’s 2012 vote share in the 73 districts is 0.55, a very strong relationship. However, much of that is driven by Kinmen and Lienchiang, where lower turnout was probably driven by a surge in household registrations by people who don’t actually live there. If we only look at the other 71 districts, the correlation is 0.26, which is still quite impressive for such a crude test. Thus, there is some evidence for the hypothesis that blue voters disproportionately stayed home.
However, let’s not overdo it. There are some people who seem to think that this was the main cause of the KMT’s defeat. There is simply no way that a drop of less than 10% in turnout can make up for a 25% gap in the presidential vote or even a gap of about 13% in the average legislative district race. Remember, many of those people who didn’t vote would have voted for the green side, so you can’t simply add 9.2% to the KMT’s total. There might have been a pattern, but it certainly did not drive the overall result. The KMT’s disaster cannot simply be blamed on poor turnout.