Can election polls be trusted in 2020?

This appeared in The Millennial Source

In the wake of the 2016 election, some observers, including many in the broader public, were surprised by Donald Trump’s victory. Much of this surprise stemmed from polling data from several swing states that showed Hillary Clinton with a solid lead, which turned out to be inaccurate — or at least misleading — on election day.

In Wisconsin, polling data in the weeks leading up to the election gave Clinton an average of a 6.5% lead, with some individual polls as high as 8%. In Michigan, similarly, Clinton had a 3.6% lead over Trump. According to the final results, Trump won Wisconsin by 0.7% and Michigan by 0.3%.

In Ohio, where Trump was polling ahead of Clinton with a 2.2% lead going into the election, Trump ended up winning by a larger margin than expected. On election day he took Ohio by 8.1%.

If the average polling results for Wisconsin, Michigan and Pennsylvania — three vital swing states — in the week leading up to the election had been correct, Clinton would have won the election. As a result, after the election there was considerable handwringing over the trustworthiness of public polls.

While some have argued that polls are weak sources of information to base election predictions due to problems with their…