Pollsters Warn Comparing Joe Biden and Hillary Clinton Is Pointless

Democratic presidential candidate Joe Biden's polling lead is reminiscent of Hillary Clinton's advantage over President Donald Trump throughout the 2016 election cycle.

And that similar advantage preceding her surprise defeat has led to speculation over the possibility of a similar result this time out.

However, despite this temptation to measure the two campaigns against each other, pollsters advise caution.

"I get comparing the polls now against the 2016 exit polls or post-election American National Election Study. That can help tell you where Biden is doing worse/better than the actual 2016 vote," Chris Jackson, head of public polling at Ipsos, told Newsweek.

"Comparing current polls against the polls at this time in 2016, however, I've never quite understood."

Expanding on this, he suggested the impact of events which altered the end result in 2016 made it hard to align the two races.

"We are pretty confident that the Comey stuff in 2016 swung late deciders so Sept 2016 polling isn't the best measure of what ended up happening that year," he said.

"Given how eventful this year is, I think it is pretty reasonable to temper any attempt to predict what will happen next."

Patrick Murray, director of the Monmouth University Polling Institute, also suggested the sway of events is difficult to factor as the campaigns "aren't travelling on the same trajectory."

He also suggested the 2020 polling appears less volatile, as there are fewer undecided voters than last time.

"Comparisons of sorts," can be made, with caveats considered for, Murray suggested, though he said the "the simplistic comparison to the 2016 polls that many are wont to do are misleading."

"Pollsters don't have crystal balls—so anything can happen," he added.

The lesser possibility of shifts was also highlighted by Mario Brossard, vice president of research at Global Strategy Group.

Early voting could be one factor which could impact this, as there is less time for situations to alter the minds of those voters.

"The fact that a lot of voters are starting to vote early, there is a lot less time for a big event to happen that changes things," he said.

Brossard also suggested that because people had seen what a Trump presidency is this time around, their minds are more likely to be made up on him.

"He's not as much of an unknown as in 2016, when events could change perceptions," he said.

On another level, difference between Biden and Clinton and the public's perception of each also changes the make-up of the race, Brossard said.

"Hillary Clinton and Joe Biden are two completely different kinds of presidential candidate," he said, suggesting Clinton received more criticism than Biden has in the run-up to the election.

Brossard said the narrative that polling was off last time, with Clinton tipped to win, was not entirely accurate.

"I think the important thing to keep in mind is that Hillary Clinton won the popular vote in 2016," he said.

"The national polling was somewhat correct, but as we know that's not how elections are done here."

Biden remains ahead of Trump in the majority of national polling ahead of November. FiveThirtyEight's poll tracker places him 6.7 points ahead, while Real Clear Politics' poll tracker puts him 6.5 points in the lead.

Newsweek has contacted the Biden campaign for comment.