Methodology

International Voting Anomaly Classification System (IVACS)

Note: We want to thank the thousands of people who shared with us the issues that they personally encountered in US elections, which we compiled into this classification system.

The International Voting Anomaly Classification System (IVACS) is a framework designed to identify and categorize anomalies in electoral processes, with a focus on election integrity. Developed to standardize the detection and reporting of irregularities in voting systems, IVACS organizes potential issues into a hierarchical taxonomy based on the nature of the anomaly — from voter registration errors to voting-machine malfunctions and ballot handling issues. By providing a consistent classification system, IVACS enables election officials, researchers, and advocates to systematically analyze vulnerabilities, improve transparency, and implement corrective measures to ensure free and fair elections. The system is particularly relevant in light of concerns about fraud, such as those raised regarding the 2020 U.S. election. IVACS can help pinpoint and mitigate risks that undermine public trust in elections.

You can find the specific code for any anomaly by using the interactive IVACS Taxonomy below.

Key Features of IVACS

Purpose

  • To standardize identification and reporting of electoral anomalies across jurisdictions.
  • To support data-driven analysis that can detect patterns of fraud, error, or manipulation.
  • To provide actionable insights for policymakers, election officials, and watchdog organizations.
  • To enable cross-country comparisons to align with global election integrity standards.

Structure

IVACS uses a four-level code to categorize anomalies:

  • Major Categories: (e.g., 2.0.0.0): Broad anomaly types, like Registration Issues.
  • Subcategories: (e.g., 2.1.0.0): Specific areas, such as Address Issues.
  • Detailed Issues: (e.g., 2.1.1.0): Clear problem types, like Voting at Wrong Address.
  • Granular Issues: (e.g., 2.1.1.1): Precise issues, such as Multiple Voters at One Wrong Address.

Major Categories

The nine major categories cover a comprehensive range of electoral anomalies:

  1. Official Roster Issues: Errors in voter lists, such as mismatches between county and state records.
  2. Registration Issues: Problems with voter registration, including address inaccuracies, invalid dates, and deceased voters.
  3. Funding Related Issues: Improper financial influences, such as vote purchasing or private funding of election processes.
  4. Individual Voting Issues: Fraudulent voting practices, like casting ballots for deceased persons or voting multiple times.
  5. Polling Location Issues: Polling site concerns, including understaffing, intimidation, or early closures.
  6. Voting Machine Issues: Technical problems with voting machines, such as interface errors, data discrepancies, or unauthorized internet connections.
  7. Ballot Issues: Problems with ballot handling, modifications, or mail-in processes, including tampering or misprinting.
  8. Pseudo Party Contributions: Partisan influences, such as biased election-related push notifications, or questionable grants.
  9. Statistics and Analysis: Statistical methods, like Benford analysis, to detect anomalies, such as impossible turnout rates.

Applications

  • Election Monitoring: Election officials can identify and address vulnerabilities in real-time.
  • Research and Advocacy: Organizations can analyze election data for potential fraud, using tools like Benford Analysis.
  • Policy Development: Legislation can be written to strengthen election security, addressing issues like non-citizen voting or invalid mail-in ballots.
  • Public Transparency: Voters have a clear, consistent framework for reporting anomalies, building trust in electoral outcomes.

Limitations

  • Evolving Election Issues: New anomalies (e.g., AI-driven disinformation, as noted in 2024 UK election threats) may require updates to the taxonomy.
  • Implementation Challenges: Data teams and election officials may require training to apply consistently across diverse electoral systems.
  • Data Verification: IVACS provides an effective way to classify data surrounding election anomalies, but the data itself must be verified to give the whole picture.

IVACS Taxonomy

IVACS taxonomy developed for global election integrity. Last updated June 2025.