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By Theodore de Macedo Soares

The 2020 South Carolina Democratic Party presidential primary was held on February 29, 2020. Election results from the computerized vote counts differed significantly from the results projected by the exit poll conducted by Edison Research and published by CNN at poll’s closing. The disparities exceed the exit poll’s margin of error.

Of all presidential candidates, Biden’s vote count exhibited the largest disparity from his exit poll projection. His unverified computer-generated vote totals represented a 8.3% increase of his projected exit poll share. Given the 528,776 voters in this election, he gained approximately 19,700 more votes than projected by the exit poll. This gain came at the expense of other candidates—mainly candidates Sanders, Warren, and Steyer.[i] Exit polls are widely recognized—such as by, for example, the United States Agency for International Development (USAID)—as a means for checking the validity of unobservable computerized vote counts.

The United States remains one of the few major democracies in the world that continue to allow computerized vote counting—not observable by the public—to determine the results of its elections.[ii] Countries such as Germany, Norway, Netherlands, France,[iii] Canada,[iv] United Kingdom, Ireland, Spain, Portugal, Italy, Denmark, Sweden, Finland and many other countries protect the integrity of their elections with publicly observable hand-counting of paper ballots.[v]



[1] Exit poll downloaded from CNN’s website by TDMS on election night, February 29, 2020 at 7:00 PM. Candidates’ exit poll percentage/proportion derived from the gender category. Number of respondents: 2018. As this first published exit poll was subsequently adjusted towards conformity with the final computerized vote count, the currently published exit poll differs from the results above.

[2] Candidates’ percentage/proportion of the total computer-generated vote counts derived from reported counts (99.96% reporting) updated on March 1, 2020 and published by Decision Desk HQ. Total number of voters: 528,726

[3] The difference between the exit poll proportion and reported vote proportion for each candidate (subtracting values in column two from the values in column three). A positive value indicates the candidate did better and received a greater share of the total reported count than projected by the exit poll. For example, candidate Biden, reported percentage/proportion of the total vote increased by 3.7% compared to his exit poll share.

[4] This column shows the percentage increase or decrease from the candidate’s exit poll projection (difference in column four divided by exit poll proportion in column two).

[5] This column presents a distinct Margin of Error (MOE) of the exit poll (EP) for the differences between candidate Biden and each of the other candidate’s EP results. The exit poll MOE, for example, between Biden and Sanders is 3.4% and the MOE between Biden and Gabbard, as her EP share is smaller, the MOE is smaller at 2.3%. MOE calculated according to multinomial formula in: Franklin, C. The ‘Margin of Error’ for Differences in Polls. University of Wisconsin, Madison, Wisconsin. October 2002, revised February 2007. Available at: https://abcnews.go.com/images/PollingUnit/MOEFranklin.pdf

[6] The disparities between the exit poll and the reported computer-generated vote counts comparing Biden and each of the other candidates (subtracting Biden’s 3.7% difference between exit poll and computer count from each of such differences for the other candidates). All disparities shown in column seven exceed their respective MOE. For example, candidate Biden’s unverified computerized vote count exceeded his EP projected vote proportion by 3.7% while Sander’s computerized count understated his EP projected vote proportion by 1.4 % for at total discrepancy of 5.1%. This 5.1% disparity, exceeding the statistical 3.4% margin of error based on their exit poll proportions, is significant as it cannot be attributed to the MOE.

[i] Sanders received 7,400 less votes than projected by the exit poll, Warren 6,400 less, and Steyer 5,000 less.

[ii] Fittingly, according to a recent Gallup World Poll, only 40% of Americans say they are confident in the honesty of U.S. elections. Finland and Norway with 89% of their citizens expressing confidence in the honesty of their elections along with the citizens of 25 other countries have greater confidence in their elections than do Americans.

[iii] During the 2007 presidential election, eighty-three municipalities (France has 36,569 municipalities) were allowed to use voting machines. Due to security concerns and the inability of voters to determine if their votes are counted correctly a moratorium, that remains today, prevents additional municipalities from introducing voting machines. In the 2012 elections only 64 municipalities continued their use. The French government desires a total ban on their use.

[iv] In Canada, the results of federal elections are determined exclusively by hand-counted paper ballots. Some provinces have adopted voting machines for local elections. See here, here and here.

[v] The United States’ long ballots–containing federal, state, and local races–are commonly cited as being unwieldy for hand-counting. The use of Sweden’s method of providing different colored paper ballots for federal, state, and local races that are then sorted prior to hand-counting addresses this objection and allows for at least the hand-counting of federal elections with only three races per ballot.

South Carolina 2020 Democratic Party Primary Exit Poll. Published by CNN at polls’ closing on election night.

Note: The exit poll vote proportions for each candidate was derived from the gender category. Candidate’s share of the male vote was multiplied with the total male proportion and added to the candidate’s proportion of the female vote multiplied with the total female vote to arrive at the candidate’s exit poll share in the state.