Measuring Vote-Selling: Field Evidence from the Philippines
Last registered on June 11, 2016

Pre-Trial

Trial Information
General Information
Title
Measuring Vote-Selling: Field Evidence from the Philippines
RCT ID
AEARCTR-0001328
Initial registration date
June 11, 2016
Last updated
June 11, 2016 4:12 PM EDT
Location(s)
Primary Investigator
Affiliation
University of Michigan
Other Primary Investigator(s)
PI Affiliation
Department of Economics and Gerald R. Ford School of Public Policy, University of Michigan
PI Affiliation
Stephen M. Ross School of Business, University of Michigan
PI Affiliation
Department of Political Science, University of Michigan
Additional Trial Information
Status
Completed
Start date
2013-04-01
End date
2013-06-30
Secondary IDs
Abstract
Using data from an anti-vote-buying field experiment we conducted in the Philippines, we report and validate a proxy measure for vote-selling. We demonstrate that our proxy measure, vote-switching, changes as expected with voter preferences and monetary offers from candidates. Voters are less likely to vote for someone different than their initial preference the larger the favorability rating difference between the preferred and alternative candidates. Similarly, vote-switching increases the more money the alternative candidate offers compared to the preferred candidates. We also describe the effects of the promise-based interventions on vote-switching, reported in full in a companion paper.
External Link(s)
Registration Citation
Citation
Hicken, Allen et al. 2016. "Measuring Vote-Selling: Field Evidence from the Philippines." AEA RCT Registry. June 11. https://doi.org/10.1257/rct.1328-1.0.
Former Citation
Hicken, Allen et al. 2016. "Measuring Vote-Selling: Field Evidence from the Philippines." AEA RCT Registry. June 11. http://www.socialscienceregistry.org/trials/1328/history/8744.
Sponsors & Partners

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Experimental Details
Interventions
Intervention(s)
Researchers in the Philippines tested whether a verbal ‘promise’ against vote-buying has any impact on voting behavior. During the May 2013 municipal elections in Sorsogon City, respondents were shown a three-minute video clip that encouraged viewers to turn out to vote, vote for honest and competent candidates, and avoid vote-selling. All respondents were then asked to rank political candidates, indicating for whom they wanted to vote in the upcoming elections, and randomly assigned to one of three groups:
(a) Promise 1 treatment group: asked to promise not to accept money from any candidates
(b) Promise 2 treatment: asked to promise to “vote your conscience,” even if they took money from a candidate.
(c) Comparison: only watched the video.
Following the elections, respondents were surveyed again.
Intervention Start Date
2013-05-01
Intervention End Date
2013-05-31
Primary Outcomes
Primary Outcomes (end points)
Vote switching
Primary Outcomes (explanation)
Vote switching: In the mayoral and vice-mayoral races, a voter is considered to have switched if she reports voting for a candidate who was not their highest rated candidate (including ties) in the baseline survey. For the city-council race, a voter switched if she voted for at least one candidate that was not in their top four highest rated candidates (including ties) in the baseline survey.
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
The experiment considers outcomes in three types of municipal elections: mayor, vice-mayor and city council in Sorsogon City. During the baseline survey, enumerators visited randomly selected households and showed them the video clip after which respondents were assigned to one of three treatment arms: promise 1, promise 2 and control.

In the month following the election, participants were surveyed a second time. Participants reported whether they had voted, and who they had voted for in each race. Voters could vote for one candidate for mayor, one candidate for vice-mayor, and up to four candidates for city council.
Experimental Design Details
Randomization Method
Done in office by computer.
Randomization Unit
Individual voter
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
Study not clustered
Sample size: planned number of observations
883 voters
Sample size (or number of clusters) by treatment arms
Control: 300
Promise Treatment 1 (accept no money): 300
Promise Treatment 2 (vote your conscience):300
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
University of Michigan
IRB Approval Date
2013-02-07
IRB Approval Number
HUM00068776
Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
Yes
Intervention Completion Date
May 31, 2013, 12:00 AM +00:00
Is data collection complete?
Yes
Data Collection Completion Date
June 30, 2013, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Study not clustered
Was attrition correlated with treatment status?
No
Final Sample Size: Total Number of Observations
748 voters
Final Sample Size (or Number of Clusters) by Treatment Arms
Control: 291 Promise Treatment 1: 298 Promise Treatment[ 2: 294
Data Publication
Data Publication
Is public data available?
Yes
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers
Abstract
MEASURING VOTE-SELLING: FIELD EVIDENCE FROM THE PHILIPPINES

Using data from an anti-vote-buying field experiment we conducted in the Philippines, we report and validate a proxy measure for vote-selling. We demonstrate that our proxy measure, vote-switching, changes as expected with voter preferences and monetary offers from candidates. Voters are less likely to vote for someone different than their initial preference the larger the favorability rating difference between the preferred and alternative candidates. Similarly, vote-switching increases the more money the alternative candidate offers compared to the preferred candidates. We also describe the effects of the promise-based interventions on vote-switching, reported in full in a companion paper.
Citation
Hicken, Allen, Stephen Leider, Nico Ravanilla, and Dean Yang. 2015. “Measuring Vote-Selling: Field Evidence from the Philippines." American Economic Review: Papers and Proceedings, May 2015.