In Hong Kong, science of crowd counting comes into focus

When Hong Kong residents took to the streets to protest a controversial extradition law on consecutive weekends this month, observers on all sides agreed the crowds were huge.

But exactly how huge is a point of contention - and reflects a growing divergence in opinion among protest organizers, police and researchers.

Organizers of the June 16 protest in the Chinese-ruled city say 2 million people took to the streets. They measured the numbers by simply counting everyone, according to Bonnie Leung of march organizer Civil Human Rights Front, although she did not say how many people they devoted to the effort.

The Hong Kong Police Force told Reuters it measured how many people were in the designated protest area - which stretched from Victoria Park in the city’s Causeway Bay neighborhood to Tamar Park, several kilometers away in Admiralty - at the time when the crowds were most dense. Their estimate: 380,000 people at the protest’s “peak”.

Academics who study crowds say scientific methods for measuring protest size depend on the type of event. For a rally in one place, they say, multiplying the average number of people per square meter by the size of the protest area gives great accuracy.

For a march, measuring the number of people passing through a given stretch of the route over a short period, and multiplying it by the duration of the event, works better.

Hong Kong University, whose Public Opinion Programme often measures the size of large events such as the annual July 1 march, did not have a survey team at either the June 9 or June 16 protests.

But judging by what he saw of the protests, Paul Yip Siu-fai, professor in the university’s social sciences faculty, said it appeared 500,000 to 800,000 took to the streets.

He emphasized, however, that trying to boil protests down to numbers missed the point.

“The actual number of people doesn’t really matter. It does matter whether you can feel that the mass of people coming out,” he said. “I think Hong Kong people are very powerful and we are very proud of this.”

Hong Kong leader Carrie Lam ignored a Thursday deadline set by some protesters to withdraw the extradition bill, which would allow criminal suspects in the former British colony to be extradited to mainland China for trial, setting the stage for a new wave of demonstrations.

- Reuters