Because of the winner takes all distributions in most states the result can flip very easily. If more states had proportional representation for the Electoral C

Because of the winner takes all distributions in most states the result can flip very easily. If more states had proportional representation for the Electoral College the confidence level would be very high. If they had just predicted the nationwide popular vote, Trump wasn't even close. The chance of him winning the popularity vote was probably in the order of < 2%.