The forensics of fraud: Evidence from the 2018 Brazilian presidential election

Objective: This paper studies the integrity of the vote counting system in Brazil. Method: We analyze data from the Superior Electoral Court (TSE) for the 2018 Brazilian presidential election to assess suspicious vote count patterns deploying five techniques commonly used to detect fraud: a) the sec...

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Main Authors: Dalson Figueiredo Filho, Lucas Silva, Ernani Carvalho
Format: Article
Language:English
Published: Elsevier 2022-01-01
Series:Forensic Science International: Synergy
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2589871X22000717
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author Dalson Figueiredo Filho
Lucas Silva
Ernani Carvalho
author_facet Dalson Figueiredo Filho
Lucas Silva
Ernani Carvalho
author_sort Dalson Figueiredo Filho
collection DOAJ
description Objective: This paper studies the integrity of the vote counting system in Brazil. Method: We analyze data from the Superior Electoral Court (TSE) for the 2018 Brazilian presidential election to assess suspicious vote count patterns deploying five techniques commonly used to detect fraud: a) the second-digit Benford's law test; b) the last digit mean; c) frequency analysis of last digits 0 and 5; d) correlation between the percentage of votes and the turnout rate; and e) resampled Kernel density of the proportion of votes. Results: The results show that the second-digit distributions for the three most voted candidates – Jair Messias Bolsonaro (PSL), Fernando Haddad (PT), and Ciro Gomes (PDT) – conform to Benford's law. We also find that last digit means and last digit frequency are within normal parameters, indicating no irregularities. Similarly, the fingerprint plot indicates a correlation coefficient that is consistent with the theoretical expectation of a fair election. The resampled Kernel density suggests that the vote count was performed without statistically significant distortions. These results are robust at different levels of data aggregation (polling station and municipality). Conclusion: The joint application of digit-focused tests, regression-based techniques, and patterns in the distribution of vote-shares provide a more reliable method for detecting anomalous cases. Relying on this unified framework, we find no evidence of electoral fraud in the 2018 Brazilian presidential election. These results advance our current understanding of statistical forensics tools and may be easily replicated to examine electoral integrity in other countries.
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spelling doaj.art-9707bbfb17b946b0afcdbdf784d691112022-12-22T04:40:33ZengElsevierForensic Science International: Synergy2589-871X2022-01-015100286The forensics of fraud: Evidence from the 2018 Brazilian presidential electionDalson Figueiredo Filho0Lucas Silva1Ernani Carvalho2Department of Political Science, Universidade Federal de Pernambuco, Recife, Pernambuco, BrazilDepartment of Medicine, Universidade Estadual de Ciências da Saúde do Estado de Alagoas, Maceió, Alagoas, Brazil; Corresponding author.Department of Political Science, Universidade Federal de Pernambuco, Recife, Pernambuco, BrazilObjective: This paper studies the integrity of the vote counting system in Brazil. Method: We analyze data from the Superior Electoral Court (TSE) for the 2018 Brazilian presidential election to assess suspicious vote count patterns deploying five techniques commonly used to detect fraud: a) the second-digit Benford's law test; b) the last digit mean; c) frequency analysis of last digits 0 and 5; d) correlation between the percentage of votes and the turnout rate; and e) resampled Kernel density of the proportion of votes. Results: The results show that the second-digit distributions for the three most voted candidates – Jair Messias Bolsonaro (PSL), Fernando Haddad (PT), and Ciro Gomes (PDT) – conform to Benford's law. We also find that last digit means and last digit frequency are within normal parameters, indicating no irregularities. Similarly, the fingerprint plot indicates a correlation coefficient that is consistent with the theoretical expectation of a fair election. The resampled Kernel density suggests that the vote count was performed without statistically significant distortions. These results are robust at different levels of data aggregation (polling station and municipality). Conclusion: The joint application of digit-focused tests, regression-based techniques, and patterns in the distribution of vote-shares provide a more reliable method for detecting anomalous cases. Relying on this unified framework, we find no evidence of electoral fraud in the 2018 Brazilian presidential election. These results advance our current understanding of statistical forensics tools and may be easily replicated to examine electoral integrity in other countries.http://www.sciencedirect.com/science/article/pii/S2589871X22000717Electoral fraudForensic analysisElections
spellingShingle Dalson Figueiredo Filho
Lucas Silva
Ernani Carvalho
The forensics of fraud: Evidence from the 2018 Brazilian presidential election
Forensic Science International: Synergy
Electoral fraud
Forensic analysis
Elections
title The forensics of fraud: Evidence from the 2018 Brazilian presidential election
title_full The forensics of fraud: Evidence from the 2018 Brazilian presidential election
title_fullStr The forensics of fraud: Evidence from the 2018 Brazilian presidential election
title_full_unstemmed The forensics of fraud: Evidence from the 2018 Brazilian presidential election
title_short The forensics of fraud: Evidence from the 2018 Brazilian presidential election
title_sort forensics of fraud evidence from the 2018 brazilian presidential election
topic Electoral fraud
Forensic analysis
Elections
url http://www.sciencedirect.com/science/article/pii/S2589871X22000717
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