The “Determinative Popular Vote”: Measuring the Margin in U.S. Presidential Elections

Presidential elections are often close; that much is clear. But the standard ways of measuring the margins in these elections—the National Popular Vote and the Electoral College Vote—paint incomplete, even misleading pictures of exactly how close they are. Due to the structure of the Electoral College, national votes do not decide the presidency. And because of state winner-take-all rules for allocating electors, Electoral College counts often inflate the gap between candidates. Both measures fail to capture how election outcomes can turn on a small number of individual votes in a few key states. This article presents a new metric that better assesses the closeness of presidential elections: the “Determinative Popular Vote” (DPV)—the minimum number of additional votes that could have altered the Electoral College outcome. We present the first comprehensively defined and historically complete analysis of this approach, calculating DPV for every election from 1836 to 2020. Our measure of closeness reveals that presidential elections are far closer than other metrics suggest. Our findings also provide new data to evaluate long-standing critiques of the Electoral College’s democratic legitimacy, including how it creates unequal voting power, allows for electoral inversions or contingent elections, and presents risks of election subversion. DPV is thus a tool for scholars, political analysts, and citizens alike to accurately measure the margin in our most consequential elections.