Working Paper: The Effect of Electronic Voting Machines on Change in Support for Bush in the 2004 Florida Elections
Michael Hout, Laura Mangels, Jennifer Carlson, Rachel Best
With the assistance of the UC Berkeley Quantitative Methods Research Team
See full report here:
..or on Scoop here
Motivation
Public discussion of changing voting technology raised concern that some forms of electronic voting might produce a
discrepancy between voters’ intentions and tabulations of the election’s outcome. In particular, touch-screen voting
machines were criticized for being unverifiable unless they printed out a hard copy that voters could certify as correct
and election officials could keep in case a recount was ordered. Without a paper trail, statistical comparisons of
jurisdictions that used e-voting are the only tool available to diagnose problems with the new technology.
In our research we used ordinary least squares and more sophisticated linear modeling approaches to assess the
statistical properties of e-voting. In particular we develop models that predict both the percentage of the votes
registered for the incumbent – President Bush – and the amount that percentage changed between 2000 and 2004. These
models can incorporate adjustments for a large number of factors that we or others thought might help explain the
patterns. These include socioeconomic and demographic factors like the typical family’s income or its ethnic ancestry.
We also adjust for ecological factors like the size of the county. Most importantly we adjust for its voting history,
reaching back not only to the 2000 election but farther to the 1996 election. To this list of factors we add
consideration of whether the county’s voting technology was e-touch machines or optical scanning equipment.
Finally we translated percentage differences into vote totals in two ways. The first was to assume that the vote margin
was due to the appearance of “ghost votes” – votes registered for in a way that helped one candidate but did not reduce
the total for the other. Mechanisms that would produce this outcome include having votes electronically registered in
the machine prior to any voters using the machine or after the last voter used it – through software errors or hacking –
and other flaws that interfere with counting after some limit is reached – reports indicate that some machines may have
been programmed to stop counting or subtract votes after some limit is reached. The second count assumes a
misattribution by the machine, i.e., a vote intended for candidate A that gets counted for candidate B. Since every vote
miscast for candidate B costs candidate A one too, the difference is doubled, so we double our initial estimate to get
our estimate of the miscount under this type of error. A combination of one type of error and the other would yield a
vote total in between.
Finding
Electronic voting raised President Bush’s advantage from the tiny edge he held in 2000 to a clearer margin of victory in
2004. The impact of e-voting was not uniform, however. Its impact was proportional to the Democratic support in the
county, i.e., it was especially large in Broward, Palm Beach, and Miami-Dade. The evidence for this is the statistical
significance of terms in our model that gauge the average impact of e-voting across Florida’s 67 counties and
statistical interaction effects that gauge its larger-than-average effect in counties where Vice President Gore did the
best in 2000 and slightly negative effect in the counties where Mr. Bush did the best in 2000. The state-wide impact of
these disparities due to electronic voting amount to 130,000 votes if we assume a “ghost vote” mechanism and twice that
– 260,000 votes – if we assume that a vote misattributed to one candidate should have been counted for the other.
See full report here: http://ucdata.berkeley.edu/new_web/VOTE2004/index.html ..or on Scoop here http://www.scoop.co.nz/stories/pdfs/election04_WP.pdf
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SUMMARY OF FINDINGS…
The Effect of Electronic Voting Machines on Change in Support for Bush in the 2004 Florida Elections
Summary:
- Irregularities associated with electronic voting machines may have awarded 130,000 excess votes or more to President
George W. Bush in Florida.
- Compared to counties with paper ballots, counties with electronic voting machines were significantly more likely to
show increases in support for President Bush between 2000 and 2004. This effect cannot be explained by differences
between counties in income, number of voters, change in voter turnout, or size of Hispanic/Latino population. - In
Broward County alone, President Bush appears to have received approximately 72,000 excess votes. - We can be 99.9% sure
that these effects are not attributable to chance.
Details:
Because many factors impact voting results, statistical tools are necessary to see the effect of touch-screen voting.
Multipleregression analysis is a statistical technique widely used in the social and physical sciences to distinguish
the individual effects of many variables.
This multiple-regression analysis takes account of the following variables by county:
- number of voters
- median income
- Hispanic population
- change in voter turnout between 2000 and 2004
- support for President Bush in 2000 election
- support for Dole in 1996 election
When one controls for these factors, the association between electronic voting and increased support for President Bush
is impossible to overlook. The data show with 99.0% certainty that a county’s use of electronic voting is associated
with a disproportionate increase in votes for President Bush.
The data used in this study come from CNN.com, the 2000 US Census, the Florida Department of State, and the Verified
Voting Foundation – all publicly available sources. This study was carried out by a group of doctoral students in the UC
Berkeley sociology department in collaboration with Professor Michael Hout, a member of the National Academy of Sciences
and the UC Berkeley Survey Research Center.
See full report here: http://ucdata.berkeley.edu/new_web/VOTE2004/index.html ..or on Scoop here http://www.scoop.co.nz/stories/pdfs/election04_WP.pdf
ENDS