The day after the election, Kathy Dopp noticed a pattern in Florida’s voting that seemed to relate to the type of voting machine used in each county. Nationwide, exit polls showed that 90% of party-registered voters tend to vote for the party to which they are registered. In Florida ’04, counties that used electronic touch-screen voting showed a shift from this expectation toward Kerry; but among counties that used opti-scan paper ballots, there was a shift toward Bush.

One suggested explanation for this pattern was that it was small counties that haven’t yet made the switch to electronic technologies, and in these areas "Dixiecrats" tend to register Democrat for local elections, but vote Republican in national elections. To test this hypothesis, Elizabeth Liddle refined Dopp’s study, eliminating the smallest counties, all of which used the opti-scan technology, and also the largest counties, which tended to use the touch-screen machines. There remained 26 mid-size counties, 8 of which use touch-screen and 18 use opti-scan. Within this group, there is no significant relationship between county size and voting technology.

A significant, unexplained relationship remained between voting technology and party shift. In the graph, opti-scan counties are represented by blue markers and touch-screen counties by red markers. County size is plotted horizontally, and party shift is the vertical axis. Upward displacement represents unexpected votes for Bush, and downward displacement is unexpected votes for Kerry. It is easy to see that the opti-scan counties shifted toward Bush, while touch-screen counties show a smaller shift toward Kerry.

On this map, just the 26 mid-size counties are shown in color. Red means opti-scan and blue means touch-screen. The opti-scan counties tended to be more in the north of the state. Still, the effect can be observed in mixed areas like the Southeast. On the right of the map, near the bottom, Red St Lucie County is sandwiched between Martin and Indian River Counties, both Blue. St Lucie County shifted to Bush, while Martin and Indian River shifted to Kerry.

Technical description of the analysis

The registration percentage was defined as R/(R+D), such that independent and third-party registrants were not part of the measure. Similarly, voting percentage was defined as Bush/(Bush+Kerry). Party shift was defined as the difference between Republican voting percentage and Republican registration percentage.

In touch-screen counties, mean party shift was -2.9% in the D direction, with a standard deviation of 3.5% (z=2.3, n=8). In opti-scan counties, mean party shift was +6.0% in the R direction, with a standard deviation of 4.9% (z=5.2, n=18).

Analysis of Variance was performed on party shift as a dependent variable, with county size and voting machine type as the two independent variables. There was no significant relationship between county size and party shift (p=0.6), but the relationship between voting technology and party shift was highly significant (p=0.00026).

Corresponding analysis for results of the 2000 election showed a similar pattern, though less pronounced. Touch-screen: mean party shift was -6.1% stdev=3.8%, (z=4.5, n=18) Opti-scan: mean party shift was +4.0% stdev=7.4%, (z=2.3, n=18) ANOVA: significant relationship between ’04 voting technology and ’00 party shift (p=0.0023) but not county size and party shift (p=0.4). Note that the same counties were analyzed with the same division, based on '04 voting technology, even though that technology was not in place in most of these counties in 2000.

Josh Mitteldorf,
Temple University, Philadelphia PA