July 27, 2015
The first Republican debate is scheduled for August 6 in Cleveland. Host Fox News is limiting the field to those ten Republicans placing highest in an average of five nationally-recognized polls. While we don't know which polls Fox will use, Ohio governor John Kasich has displaced former Texas governor Rick Perry for the final spot based on the 270toWin five-poll average. Businessman Donald Trump has won all five of these polls.
The ten-candidate cutoff has received a lot of criticism, and rightly so. Assuming a poll of 500 people, the difference between Chris Christie in 9th place averaging 3.2% and Bobby Jindal in 14th place at 1.2% is just 10 people. That is before factoring in the statistical errors inherent in polling: Some of these polls have sample sizes small enough that almost everyone outside the top 3 is within the margin of error. Yet another issue is that the polling is national, while the choice of a nominee will be done via the primary and caucus system at the state level. Some of those not expected to make the cut are polling well in one or more states, based on their regional strength.
In sum, Fox is choosing ten debate participants based on insignificant differences in polls for an election that doesn't exist.