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Fact check: What methods are used to accurately count attendance at political events and parades?

Checked on June 16, 2025

1. Summary of the results

There are several established methods for counting attendance at political events and parades, ranging from traditional techniques to modern technological solutions. Traditional approaches include the Jacobs Method/Crowd Formula, which calculates crowd density per square meter [1] [2], and controlled entry counting through gates/turnstiles [1]. Modern technological solutions include:

  • Aerial imagery analysis through:
  • Satellites
  • Helicopters/balloons
  • Drones with AI processing
  • Statistical motion tracking [2]
  • Supplementary data collection via:
  • CCTV footage
  • Thermal cameras
  • Public transport usage
  • Phone location tracking
  • Mobile network data [2]

A notable advancement is the University of São Paulo's AI-powered drone tool, which has reduced its margin of error from 30% to 12% since 2022 [3].

2. Missing context/alternative viewpoints

Several crucial contextual factors affect crowd counting accuracy:

  • Inherent challenges including:
  • Irregular crowd shapes
  • Hidden areas
  • Movement patterns [1]
  • Reliability concerns: Mathematician Hannah Fry notes there's often an "incentive to exaggerate" crowd sizes [1]. The traditional density-based methods are "usually a guess" according to researchers [3].
  • Best practices: Experts recommend using multiple techniques and cross-referencing estimates rather than relying on a single method [1].

3. Potential misinformation/bias in the original statement

The question assumes there are "accurate" methods for counting crowds, when in reality, even the most advanced technologies have significant margins of error. Different stakeholders may present different numbers based on their interests:

  • Event organizers might inflate numbers to demonstrate support
  • Opposition groups might minimize numbers
  • Law enforcement and media might have their own biases in reporting [1]

This is why experts emphasize the importance of using multiple methods and cross-referencing different sources to achieve the most reliable estimate, rather than seeking a single "accurate" count [1] [2].

Want to dive deeper?
How do crowd estimation techniques differ between law enforcement and event organizers?
What role does aerial photography play in estimating political rally attendance?
Why do attendance figures for the same political event often vary dramatically between sources?
What are the most accurate scientific methods for counting large crowd sizes at outdoor events?
How do political campaigns typically inflate or deflate attendance numbers for strategic purposes?