But while polling accuracy was mediocre in 2020, it also wasn’t any sort of historical outlier. The overall average error of 6.3 points in 2019-20 is only slightly worse than the average error across all polls since 1998, which is 6.0 points. There were also presidential years before the period our pollster ratings cover, such as in 1948 and 1980, when the polls exhibited notably larger errors than in 2020.6
So while the polling industry has major challenges — including, as we’ll detail later, the fact that live-caller telephone polls may no longer be the industry gold standard — it’s also premature to conclude that the sky is falling. As you can see from the chart above, there isn’t any particularly clear statistical trend showing that polls have gotten worse over time. Yes, both 2016 and 2020 were rather poor years, but sandwiched between them was an excellent year for the polls in 2018. And in their most recent test, the Georgia Senate runoffs, the polls were extremely accurate.
Of course, there’s a lot more to unpack here. Why have the polls been pretty accurate in recent years in “emerging” swing states, such as Georgia and Arizona, but largely terrible in the Upper Midwest? Why did they do poorly in 2016 and 2020 but pretty well in Trump-era elections — like the Georgia runoffs or the Alabama Senate special election in 2017 — when Trump himself wasn’t on the ballot? We don’t really have time to explore the landscape of theories in the midst of this already very long article, although these are topics we’ve frequently covered at FiveThirtyEight. At the same time, I hope this macro-level view has been helpful and an evolution beyond the somewhat misinformed “polling is broken!” narrative.