Essentially this.
I'd also like to add the following to the subject. One of the biggest myths about 2016 is how the polls didn't predict Trump's victory...except that they did if you were looking at the data with a critical eye.
To begin with the average of national polling showed Hillary winning by 3 points in popular vote, she won by 2, well within the margin of error of those polls. One could argue state polls got it wrong, but there you had very few polls to go by.
As for how one could predict Trump would win? Simple: In the vast majority of polls of 2016, including state ones, one could see that beyond the support Trump and Hillary had there were a huge number of people showing up as undecided, even in the double digits, this was more then enough to offset the difference between Hillary and Trump and decidedly in Trump's favor who had a lot of people that voted for him that would never admit it because of social backlash.