Can we trust Presidential polls?

This isn't the first time politicians and pundits have questioned the accuracy of polling data

(CNN) – Donald Trump has made headlines recently for attacking the legitimacy of polls that show him trailing Clinton.

This isn’t the first time politicians and pundits have questioned the accuracy of polling data. In 2012, Barack Obama is fighting for re-election and republicans are furious saying polls showing him with a significant lead over Mitt Romney are ‘skewed’ in favor of democrats and dead wrong.

“Romney will win this election by five to ten points in the popular vote – and will carry more than 300 electoral votes,” said Dick Morris back during the Obama-Romney election.

By Election Day, the polls have tightened to a deadlock, but the final result is anything but, the president cruises to re-election, beating Romney fifty-one to forty-seven percent.

“CNN projects the Republicans will control of the United States Senate,” said Wolf Blitzer in the past.

The GOP takes the Senate, tightens its grip on the house, and seizes more governorships too. It all encourages doubt and gives anyone losing in the polls an easy complaint.

“Even the polls are crooked. Look, we’re in a rigged system folks,” said Trump.

Pollsters are undeniably facing challenges, fewer voters willing to participate; new technology like computerized calling which makes some polls cheaper, faster and at times less accurate.

And unbelievably close races with rapidly evolving news cycles can lead to occasional mistakes which have always plagued the polling business.

Still, for all those troubles, presidential polls remain among the most accurate. Yes, there is still a margin for error, meaning the actual vote may be a little higher or lower than a poll predicts for any given candidate. But the vote will almost always fall within that margin.

Continuing Coverage: Decision 2016