Published November 3, 2024
Readers of my Post piece predicting Donald Trump will win and Republicans will have a good night in congressional contests may wonder how I derived the numbers underlying those calls.
Here I examine that in detail and show why getting the balance between Democrats and Republicans among voters — partisan preference — is the key unlocking the polls.
Polling’s theoretical accuracy relies on the statistics underlying the relation between a random sample and the broader population it’s drawn from. But surveyors can no longer get truly random samples because cellphones and the Internet have changed how people live.
Pollsters have reacted to this in a variety of ways, but they all rely on something called weighting the sample. That means they use different ways to get their sample — calling a mixture of cellphones and landlines, for example, or using online samples. It also means taking those raw data and assigning different values — “weights” — to each respondent based on what share of the likely electorate that person possesses.
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Henry Olsen, a senior fellow at the Ethics and Public Policy Center, studies and provides commentary on American politics. His work focuses on how America’s political order is being upended by populist challenges, from the left and the right. He also studies populism’s impact in other democracies in the developed world.
