No matter how many times people make the claim, it is simply wrong to say that 81 percent of white evangelicals in the United States voted for Donald Trump to become president.
First (and I know this is quibbling), the number that people are meaning to cite is actually 80 percent.
(Media originally reported 81 percent, but that was based on initial reports of the exit poll before the tabulations were complete.)
Second, the statistic was not purporting to measure the total percentage of all white self-identified evangelicals.
Rather, the number is supposed to indicate the number of white voters who self-identify as born-again or evangelicals and voted for Trump.
That sounds like mere semantics, but it actually represents a significant difference. Evangelical historian Thomas Kidd uses recent statistical analysis to estimate that 40 percent of white evangelicals didn’t vote in this election (see, e.g., this).
If we then grant the 80 percent figure for the remaining 60 percent who did vote ended up casting their ballot for Trump, then it would be the case that less than half (48 percent) of white self-identified evangelicals voted for Donald Trump.
Stop Saying 81 Percent of White Evangelicals Vote for Trump (It Was Probably Less Than Half) https://t.co/R73SFtcp7g
— Mike McGarry (@RevMcGarry) December 14, 2018