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The Effect of Prepaid Postage on Turnout: A Cautionary Tale for Election Administrators
Last registered on November 04, 2016

Pre-Trial

Trial Information
General Information
Title
The Effect of Prepaid Postage on Turnout: A Cautionary Tale for Election Administrators
RCT ID
AEARCTR-0001462
Initial registration date
November 04, 2016
Last updated
November 04, 2016 9:03 PM EDT
Location(s)
Primary Investigator
Affiliation
Columbia University
Other Primary Investigator(s)
PI Affiliation
Assistant professor, Department of Politics at Princeton University
PI Affiliation
Professor of political science, Menlo College
PI Affiliation
Political science Ph.D. candidate, Yale University
PI Affiliation
Associate professor in the Department of Economics, Loyola Marymount University
PI Affiliation
Associate professor, Graduate School of Business Stanford University
Additional Trial Information
Status
Completed
Start date
2010-01-01
End date
2010-11-01
Secondary IDs
Abstract
In collaboration with local election officials, we conducted a randomized field experiment in which postage-paid envelopes were provided to a random sample of 10,000 permanent vote-by-mail (VBM) voters in San Mateo County, California, in advance of the November 2, 2010, general election. We find that the treatment generated statistically significant but unexpected effects: postage-paid envelopes increased the probability that voters cast their ballots in person and decreased the probability that they cast their ballots by mail. These offsetting effects meant that the intervention produced no net change in voter turnout. We find that this pattern of countervailing effects is strongest among voters who frequently voted by mail in the past, those potentially most susceptible to disruptions in routine. Post-election interviews support the idea that the postage-paid envelopes created confusion for some voters. The results suggest that reforms designed to increase turnout by decreasing voting costs may have the unintended effect of disrupting routines.
External Link(s)
Registration Citation
Citation
Carnegie, Allison et al. 2016. "The Effect of Prepaid Postage on Turnout: A Cautionary Tale for Election Administrators." AEA RCT Registry. November 04. https://doi.org/10.1257/rct.1462-1.0.
Former Citation
Carnegie, Allison et al. 2016. "The Effect of Prepaid Postage on Turnout: A Cautionary Tale for Election Administrators." AEA RCT Registry. November 04. https://www.socialscienceregistry.org/trials/1462/history/11631.
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Experimental Details
Interventions
Intervention(s)
Researchers randomly provided postage-paid envelopes to a subset of permanent absentee voters in San Mateo County, California in order to evaluate its impact on voter turnout. Treatment-group individuals were sent a postage paid envelope with their absentee ballot. In addition, individuals also received an insert with voting instructions. The front sides of both treatment and control inserts were identical but the instructions on the back of the inserts sent to the treatment group voters noted that postage was not required, while control group voters were provided standard instructions. The prepaid envelopes and appropriate instruction sheets were inserted into the ballot mailings and were sent out in the same manner as the control-group ballots.
Intervention Start Date
2010-01-01
Intervention End Date
2010-11-01
Primary Outcomes
Primary Outcomes (end points)
1) Voter turnout
2) Method of voting if any (abstain, in person, by mail)
Primary Outcomes (explanation)
After Election Day, researchers obtained an updated voter file from the San Mateo County Registrar of Voters, which provided validated turnout information for individuals in treatment and control groups. San Mateo County records whether each voter cast a ballot by mail, in person on Election Day, or in person during the early voting period.
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
From a list of 148,000 registered permanent absentee voters in San Mateo County, 10000 were randomly selected to be in the treatment group. Assignment of voters to the treatment was clustered by household. In other words, all voters registered at the same address received the same set of voting instructions so that people in the same household were not exposed to different treatments. Treatment voters received postage paid envelopes with their mailed in ballot while control voters received the usual envelopes with their ballot. Voting records for both control and treatment groups were collected from the Registrar of Voters.
Experimental Design Details
Randomization Method
By computer
Randomization Unit
Household (voters registered at the same address received the same set of voting instructions)
Was the treatment clustered?
Yes
Experiment Characteristics
Sample size: planned number of clusters
99,214
Sample size: planned number of observations
148,840 permanent absentee voters
Sample size (or number of clusters) by treatment arms
Treatment: 10,000 permanent absentee voters
Control: 138,840 permanent absentee voters
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
IRB Approval Date
IRB Approval Number
Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
Yes
Intervention Completion Date
November 01, 2010, 12:00 AM +00:00
Is data collection complete?
Yes
Data Collection Completion Date
November 01, 2010, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
148,840 permanent absentee voters
Final Sample Size (or Number of Clusters) by Treatment Arms
Treatment: 10,000 permanent absentee voters Control: 138, 840 permanent absentee voters
Data Publication
Data Publication
Is public data available?
No
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers
Abstract
THE EFFECT OF PREPAID POSTAGE ON TURNOUT: A CAUTIONARY TALE FOR ELECTION ADMINISTRATORS

In collaboration with local election officials, we conducted a randomized field experiment in which postage-paid envelopes were provided to a random sample of 10,000 permanent vote-by-mail (VBM) voters in San Mateo County, California, in advance of the November 2, 2010, general election. We find that the treatment generated statistically significant but unexpected effects: postage-paid envelopes increased the probability that voters cast their ballots in person and decreased the probability that they cast their ballots by mail. These offsetting effects meant that the intervention produced no net change in voter turnout. We find that this pattern of countervailing effects is strongest among voters who frequently voted by mail in the past, those potentially most susceptible to disruptions in routine. Post-election interviews support the idea that the postage-paid envelopes created confusion for some voters. The results suggest that reforms designed to increase turnout by decreasing voting costs may have the unintended effect of disrupting routines.
Citation
: Michelson, Melissa R., Neil Malhotra, Andrew Healy, Donald P. Green, Allison Carnegie, and Ali Adam Valenzuela. 2012. "The Effect of Prepaid Postage on Voter Turnout: A Cautionary Tale for Election Administrators." Election Law Journal 11(3): 279-290.