a measure of early voting opportunity that is the average number of early voting hours available
in a county (i.e., the total number of hours available for early voting across all sites in the county
divided by the number of early voting sites in the county).
Our measure of elite early voting mobilization is the number of activities the party chair
reports doing out of a possible set of seven (encouraging early voting, providing transportation,
advertising, promoting registration, attending social activities, working through a religious
organization or “something else”) to target voters for early voting. The scale ranges from zero
(no activities performed in the 2002 election) to 7. The Cronbach Alpha for the early voting
scale is 0.79 for Democratic chairs and 0.74 for Republican chairs.
We estimate models of validated voter turnout that consist of individual-level
characteristics, the reports of county chairs on mobilization efforts devoted to early voting, and
the institutional availability of early voting in the respondent’s county. Our theoretical
expectations require that the model explicitly tests for the interaction of elite mobilization efforts
with the availability of early voting in the county, and that these effects are estimated separately
for Democratic and Republican mobilization.
Because party chairs are expected to target their supporters, we must also estimate the
effects of Democratic and Republican mobilization on co-partisans (i.e., Democratic identifiers
and Republican identifiers) separately, as opposed to estimating their effects on the entire sample
of registered voters. We thus estimate two similar turnout models that differ in two respects.
The first difference is whether the party early voting mobilization measure used is that provided
by the Republican or Democratic party chair. We include either the Republican or Democratic
early voting mobilization measure in the model separately but also include it as an interaction
term multiplied by the early voting opportunity scale. This interaction term reflects our
argument that the effects of early voting are contingent on elite efforts to use the reform.
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Convention