From Darren Samuelsohn writing at Politico:

Beltway insiders like to dismiss Donald Trump’s strength in social media as a mirage – a following of reporters and political gadflies, not Republican voters and core activists.

New data shows the Washington elite are wrong.

According to an analysis obtained by POLITICO that matches Twitter handles to public voter data, seven out of every 10 of @realdonaldtrump’s followers appear to be his supporters. The report, produced by San Antonio database marketing agency Stirista, also found that nearly 90 percent of Trump’s followers are reliable turn outs at the ballot box; roughly 11 percent of Trump’s followers should be classified as first-time presidential voters.

“It’s translating into votes,” Stirista CEO Ajay Gupta said in an interview to describe Trump’s social media strategy. “Not at a one-to-one level. But at a 70 percent level, it is a pretty good margin.”

Stirista’s analysis tries to grapple with the still difficult-to-measure effect of social media on Election Day results amid one of the most engaging online presidential races in U.S. history, and one that, thanks to Trump, has upended traditional White House campaign practices.