Information Dissemination Campaign and Voters' Behavior in the 2009 Municipal Elections in Mexico

Alberto Chong
Jalisco, Morelos, Tabasco, Mexico
2,360 voting precincts
2009 - 2009
Target group:
  • Voters
Outcome of interest:
  • Electoral participation
  • Transparency and accountability
  • Corruption and Leakages
Intervention type:
  • Information
AEA RCT registration number:

In order to examine whether offering more information to voters about their incumbents’ performance strengthens electoral accountability, researchers randomly assigned voting precincts to a campaign spreading information on corruption and public expenditure conducted one week before the 2009 municipal elections in Mexico. Providing incumbent corruption information not only decreased incumbent party support, but also decreased voter turnout and support for the challenger party, as well as eroded partisan attachments. While information clearly is necessary to improve accountability, corruption information is not sufficient because voters may respond to it by withdrawing from the political process.

Policy issue

It is widely held that access to information is a vital component of democracy building and government accountability. A recent World Bank report champions information as “a tool to empower citizens in developing countries to hold their public agents accountable.”1 Information flows, the report argues, not only enhance democratic participation, but also make democracy work for ordinary people. However, while evidence suggests that access to information may lead voters to punish corrupt incumbents, it is unclear whether this translates into increased support for challengers and higher political participation. In other words, information about corruption may not improve political accountability, if voters respond to it by withdrawing from the political process.

Context of the evaluation

Despite optimistic views about fiscal decentralization in Mexico, local governments’ performance has remained poor. In 2008, for example, more than 80 percent of municipal governments’ resources were spent either on the bureaucracy or were unaccounted for. While elections should enable voters to discipline their mayors, a single-term limit is imposed on all elected officials in Mexico. Thus, the immediate fate of mayors is determined not by voters but by their political party. To reconcile the single-term limit with accountability, scholars have typically assumed that voters punish or reward the incumbent party for mayoral performance. However, there is little evidence that government performance impacts the subsequent election—previous work shows a strong entrenchment of incumbents from all political parties.

Further impeding voters’ ability to hold mayors accountable are widespread misconceptions about which public works and services municipal authorities are responsible for providing, as well as a lack of available information about the amount of money municipalities receive and how this money is spent. In an attempt to ensure greater municipal accountability, a 1999 constitutional reform established the Federal Auditor's Office (ASF). On a yearly basis, the ASF selects a sample of municipalities in each state to audit. The results of the audits are published in lengthy reports, which are made available online. Though public, these reports are rarely used by media or political parties in local campaigns because the release date of the reports is not aligned with the timing of elections.

Photo: Frontpage |

Details of the intervention

Researchers sought to assess the effects of information dissemination on participation in the 2009 municipal and congressional elections in Mexico. Approximately one week before Election Day, researchers randomly assigned voting precincts to one of three types of information campaigns, or the comparison group, which received no information. In all three information campaigns, all flyers stated that it was the mayor’s responsibility to provide public lighting, safe water, sewage, and local roads. All flyers also included information on the total amount of resources available to the mayor in that particular municipality to invest in public services, and the amount the mayor actually spent. In the first of three treatment groups, the “corruption information” group, the flyer included information about the percentage of resources the mayor spent in a corrupt manner—with corruption defined as public spending with some form of irregularity such as over-invoicing, fake receipts, diverting resources, fraud, etc. The two other treatment groups were placebos. In one, the “budget expenditure” group, the flyer included only information about the percent of resources spent by the end of the fiscal year. In the other, the “poverty expenditure” group, the flyer included information about the percent of resources mayors directed toward improving services for low-income households. In total, 150 electoral precincts were randomly assigned to each of the three interventions, for a total of 450 treated precincts and 1910 precincts in the comparison group.

Researchers gathered demographic characteristics from census data, and then collected electoral results for each precinct from the electoral institutes for each state. This information was complemented by a follow-up survey collected ten days after the election.

Results and policy lessons

Effect on people’s beliefs and opinions: Overall, providing corruption information did not change people’s beliefs, suggesting that for most voters, the information confirmed what they already believed, that the government was dishonest. However, exposing high levels of corruption led people to believe their municipal government was more dishonest and increased their dissatisfaction with public services. Neither placebo group—the budget expenditure or the poverty expenditure treatment—had any effect on individuals’ beliefs or opinions.

Effects on electoral outcomes: Disseminating information about corruption led to a 1.3 percentage point (2.5 percent) decrease in voter turnout, a 0.4 percentage point (2.5 percent) decrease in the incumbent parties’ votes, and a 0.86 percentage point (2.7 percent) decrease in challengers’ votes. To get a sense of the substantive importance of these effects, consider that the average margin of victory was 8 percent among municipalities in the study. In contrast, providing information about overall spending and distributive allocations in the placebo groups had no impact on voter turnout, or the incumbent or challenger’s support.

The level of corruption exposed affected the impact on voter turnout, and incumbent and challenger’s support. Disseminating information about low vs. high levels of corruption reduced voter turnout by 1.8 (3.4 percent) and 7 percentage points (13.7 percent), respectively. The treatment group that received information on low corruption cast 0.67 percentage points (3.7 percent) fewer votes for the incumbent parties and 1.10 percentage points (3.2 percent) fewer for the challengers, while the treatment group that received information about high corruption cast 2.6 percentage points (14.8 percent) fewer votes for the incumbent parties and 4.5 percentage points (13.1 percent) fewer votes for the challengers.

Effects on partisan attachment: Respondents who were provided with information about corruption were 0.1 percentage points (46 percent) less likely to identify with the incumbent party than those in one of the placebo groups. Incumbent corruption information had no discernible effect on identification with theprocess.

Chong, Alberto, Ana De La O, Dean Karlan, and Leonard Wantchekon. 2014. ‰ÛÏDoes Corruption Information Inspire the Fight or Quash the Hope? A Field Experiment in Mexico on Voter Turnout, Choice and Party Identification.‰Û� Journal of Politics, Forthcoming.
Khemani, Stuti. 2007. Can Information Campaigns Overcome Political Obstacles to Serving the Poor? The Politics of Service Delivery in Democracies.