Research Shows: Direct Mail Changes Campaign Outcomes

This fall, research by Joel Middleton of UC Berkeley and Todd Rogers at the Harvard Kennedy School confirmed that direct mail voter guides have substantial effects on modern elections.

The pair evaluated the effectiveness of a non-profit group’s direct mail communication efforts to sway voters on 10 ballot initiatives in the 2008 election in Oregon.

The nonprofit sent persuasive ballot guides to nearly 90 percent of households in the state. To examine their impact, the study used a randomized controlled experiment, where some precincts were randomly assigned to a control group that did not receive the ballot guides, while other precincts were assigned to receive the guides. The results show a significant effect: the ballot guides moved the vote margin by about 4 percentage points in the intended direction in each of the 10 ballot measures. This suggests that, on each of the measures, approximately 1 in 50 voters switched their vote specifically because they received the mailer.

In fact, the ballot guides appear to have directly caused two initiatives to be rejected by voters – Measure 61 lost by a 2.1 percentage point margin, while the ballot guide moved the vote margin by over 5 percentage points; and Measure 64 failed by a margin of 1 percentage point, while the ballot guide moved the vote margin by over 5 percentage points.

Even in today’s increasingly digital world, this study shows that not only can direct mail communications bolster campaigns – but that campaigns can effectively direct whether an initiative becomes law or a person becomes elected.