The Empirical Frequency of a Pivotal Vote

Casey B. Mulligan, Charles G. Hunter

NBER Working Paper No. 8590
Issued in November 2001
NBER Program(s):Economic Fluctuations and Growth, Public Economics

Empirical distributions of election margins are computing using data on U.S. Congressional and state legislator election returns. We present some of the first empirical calculations of the frequency of close elections, showing that one of every 100,000 votes cast in U.S. elections, and one of every 15,000 votes cast in state elections, 'mattered' in the sense that they were cast for a candidate that officially tied or won by one vote. Very close elections are more rare than the independent binomial model predicts. The evidence also suggests that recounts, and other margin-specific election procedures, are quite relevant determinants of the frequency of a pivotal vote. Although moderately close elections (winning margin of less than ten percentage points) are more common than landslides, the distribution of moderately close U.S. election margins is approximately uniform. The distribution of state legislature election margins is clearly monotonic, with closer margins more likely, except for very close and very lopsided elections. We find an inverse relationship between election size and the frequency of one vote margins in both data sets over a wide range of election sizes, with the exception of the smallest U.S. elections for which the frequency increases with election size.

download in pdf format
   (509 K)

email paper

Machine-readable bibliographic record - MARC, RIS, BibTeX

Document Object Identifier (DOI): 10.3386/w8590

Published: Mulligan, Casey B and Charles G. Hunter. "The Empirical Frequency Of A Pivotal Vote," Public Choice, 2003, v116(1-2,Jul), 31-54. citation courtesy of

Users who downloaded this paper also downloaded* these:
Gelman, Silver, and Edlin w15220 What is the probability your vote will make a difference?
Nordhaus w12813 The Economics of Hurricanes in the United States
Borjas and Katz w11281 The Evolution of the Mexican-Born Workforce in the United States
Edlin, Gelman, and Kaplan w13562 Voting as a Rational Choice: Why and How People Vote to Improve the Well-Being of Others
Allcott, Diamond, Dubé, Handbury, Rahkovsky, and Schnell w24094 Food Deserts and the Causes of Nutritional Inequality
NBER Videos

National Bureau of Economic Research, 1050 Massachusetts Ave., Cambridge, MA 02138; 617-868-3900; email:

Contact Us