There were crowds of people at the Paris 2024 Olympic Games and the media had a grand time estimating the numbers. That had me thinking about crowds – at political rallies, protests and demonstrations, celebratory parades, department sales, concerts, and sporting events.
I remember ten years or so ago, after a political rally, the estimation of crowd numbers varied across three different sources: the police estimated 30,000 and the political party estimated 300,000. Independent observers suggested 80,000.
There is a way to count a crowd – still an estimate, but a more accurate estimate to mitigate groups that disseminate misinformation, disinformation, and harmful content that overstates, exaggerates, and inflates the figures for their own purposes. Granted, it’s not easy with a moving crowd, but it is still possible if the counters take a little more time and a little more care.
One method is that of Berkeley journalism professor, Herbert Jacobs, emerging from the 1960s during America’s countercultural movement. And not just in America. Remember The Who singing about “My generation” in 1965? This is my generation, baby! Civil rights movements, anti-war movements, the 1969 Woodstock music festival, and the 1963 March on Washington for Jobs and Freedom – otherwise known as The March, or the “I have a dream” March, or the Freedom March.
The Million Man March in Washington in 1995 replicated the Freedom March of the 60s, but it wasn’t a march, as such – it was a gathering. Conflict later ensued about the estimation of the crowd numbers. The National Park Service, who had photographs taken from helicopters, estimated 400,000 people. The organizers of the march said there were a lot more – a heck of a lot more, at two million. Some media outlets funded researchers at the Centre for Remote Sensing at the University of Boston to check the numbers and, using a computer program, they estimated the crowd to be “about 837,000 members, with a 20% margin of error.”
There was a lot of “movement” in the 60s. The Free Speech Movement had its roots in 1964 at the University of California, Berkeley, when students protested, rising from small sit-ins to large rallies. Herbert Jacobs (1903-1987) was present at the university during the unrest, known as the Berkeley riots. His office overlooked the plaza where students gathered. He noted that the plaza was marked with regular grid lines.
It’s about the proximity of people, he suggested.
According to the Jacobs Method, the area in which the crowd is congregating should be divided into smaller sections to determine the proximity of people. If people stand at arm’s distance, one person will cover 0.93 square metres (10 square feet). If people stand close but are not pushing each other, the area of one person is estimated at 0.42 square metres (4.5 square feet). In a tightly packed crowd, 0.23 square metres (2.5 square feet) is covered by one person (in other words, about four people in one square metre).
Jacobs assessed the plaza crowd visually from his office window. Nowadays, it should be easier to estimate crowd numbers due to advancements in aerial photography and drone images.
Jacobs used the grid lines in the plaza to divide the crowd into “parcels” or blocks, squares, or segments. He had to do this rapidly, looking at several grid squares and taking the average of them.
With a photograph of the crowd, grid lines can be drawn to segment the area into squares. For more accurate data, information from several photographs of the same crowd can be triangulated. For example, with 20 photographs, there might be 40 or more segmented squares. An estimation might show that there were 30,000 people in 15 of the total 40 squares analysed from the photographs.
The Jacobs Method is used as an estimation, plus or minus 20%. The numbers are still problematic, but the Jacobs Method is as good as it gets for a quick assessment of crowd numbers.
So, it's true that methods for counting crowds have existed for decades, but people prefer to make a wild guess rather than a more educated guess. I use the Jacobs Method visually for a rapid response or wait until media outlets produce aerial photographs and apply the same method for a more nuanced response.
The Herbert Jacobs Method for counting crowds is still used by “serious” crowd counters today, but more and more, people wait for post-event aerial photographs for greater accuracy before applying the same method or something fancier.
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Photographer: Martina Nicolls