In the past week, most presidential election polls have shown Democratic candidate Joe Biden leading in his race against President Trump. Some pollsters found the margin to be thin: anywhere from 1 percentage point to 6 or 8. Others, crunching their numbers differently or crunching different numbers, have found overwhelming public preference for Biden, with leads of 17, 18, even 25 points. One poll found Biden to be trailing Trump by 1 point. Among election junkies, in newsrooms and on social media, each of these polling results makes for a likely conversation topic, headline, or tweet. Everyone likes to watch the horse race, and polling numbers are as close as anyone has to live running commentary on how their horse is doing.
Paying attention to poll results isn’t just a way to turn the democratic process into a sport. Polling results may also influence voter behavior. Some experts attribute the low voter turnout of the 1996 presidential election to polls showing Bill Clinton leading Bob Dole by a wide margin. Now, President Trump’s deficit in the polls has created some conversation about whether he should drop out of the race. Conversely, close polling numbers may stir excitement and motivate people to head to the voting booth. For something with such a firm grip on the news cycle and voter behavior, though, polls themselves often look mysterious and murky to the general public. The numbers arrive daily from the mist, and few people really question how they got there.
That vagueness, while understandable, is also easy to exploit for political gain. Not all polling data is of equal value and quality—far from it. Take polls reporting that Biden is leading Trump by 2 percentage points. “That’s meaningless,” says Jennifer Stromer-Galley, who researches digital politics and campaigning at Syracuse University. “If it’s a good poll, then it’s within the margin of error, which is usually 3 to 5 percentage points.”
Even polling results