Feeding the five thousand -- or was it three? Researchers claim most crowd estimations are unreliable

ScienceDaily (Aug. 26, 2011) — The public should view crowd estimation with skepticism, say the authors of a study published in Significance, the magazine of the Royal Statistical Society and the American Statistical Association, as they suggest more reliable alternatives to current estimating methods.

Estimates of crowd sizes vary greatly, and the success of an event is often measured by the size of the crowd. Organizers of the 2007 "Stop the War" demonstration in London reported crowds of 60,000, whereas the police reported just 10,000. The US Government's estimate of the crowds at Obama's inauguration ceremony was 1.8 million, while other estimates were much less, closer to one million. "In the absence of any accurate estimation methods, the public are left with a view of the truth colored by the beliefs of the people making the estimates," claims Professor Paul Yip, of the University of Hong Kong, one of the authors of the study.

Such a huge discrepancy in estimates is currently not unusual and suggests the use of crowd sizes as a political tool. Larger crowd sizes are a means of recruiting others to the cause, and it is more difficult for the authorities to ignore demands. "The authorities are sometimes put in a difficult position," says Yip. "It is important to highlight the shortcomings of existing estimating methods."

In this latest study, the authors reveal several more accurate, more reliable methods of estimating crowd sizes. Currently, even when searching for the truth, there is a wide margin of error. The authors recommend organizers and authorities use an area x density estimating method for static crowds, which reduces the margin of error to less than 10%. Furthermore, they have devised an entirely new method of reliably estimating mobile crowds. Two inspection points are placed along the route where the number of participants is estimated, not too close together and with one near the end. In applying this two-inspection-point method to the Hong Kong 1st July march (a demonstration of widely-varying claimed size and of great political sensitivity) since 2003, more reliable estimates can then be obtained.

"It is important to rectify the myth of counting people. The public would be better served by estimates less open to political bias. Our study shows that crowd estimates with a margin of error of less than 10% can be achieved with the proposed method," Yip concludes.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Wiley-Blackwell, via AlphaGalileo.

Journal Reference:

Ray Watson, Paul Yip. How many were there when it mattered? Estimating the sizes of crowds. Significance, September 2011: 104-107 DOI: 10.1111/j.1740-9713.2011.00502.x

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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Saudi Arabia’s Kingdom Tower to claim world’s tallest building title

 The Kingdom Tower will stand over one kilometer tallImage Gallery (9 images)

Chicago-based firm Adrian Smith + Gordon Gill (AS+GG) has officially been announced as the design architects for the Kingdom Tower that is to be built in Jeddah, Saudi Arabia. Initially planned to stand one mile (1.6 km) high and be called the Mile-High Tower, the building was scaled down after soil testing in the area in 2008 cast doubt over whether the location could support a building of that height. Now the building will stand over 0.62 miles (one kilometer) tall, which will still allow it to overshadow the 2,717 ft. (828 m) Burj Khalifa to claim the title of the world's tallest building.

The Kingdom Tower will be the centerpiece and first construction phase of Kingdom City, a 57 million square foot (5.3 million m2) development located along the Red Sea north of Jeddah, which is known as the traditional gateway to the holy city of Mecca. The entire development has been budgeted at US$20 billion, with the Kingdom Tower alone costing approximately $1.2 billion to construct and covering an area of 5.7 million square feet (530,000 m2).

The building will contain 59 elevators, including 54 single-deck and five double-deck elevators, as well as 12 escalators. The elevators serving the observatory will travel at 22 mph (36 km/h) in both directions. At level 157, a sky terrace roughly 98 feet (30 m) in diameter intended as an outdoor amenity for use by the penthouse floor extends from the side of the building.

The exterior wall system is designed to minimize energy consumption by reducing thermal loads, while a series of notches on the building's three sides create pockets of shadow that shield areas of the building from direct sunlight and provide outdoor terraces.

The three-sided tower rises from a three-petal footprint design with aerodynamic tapering wings that help reduce structural loading due to wind vortex shedding. Gill says the tower's sleek, streamlined form was inspired by the folded fronds of young desert plant growth.

"With its slender, subtly asymmetrical massing, the tower evokes a bundle of leaves shooting up from the ground - a burst of new life that heralds more growth all around it," added Smith.

While the building's exact height isn't yet known, when completed AS+GG claim it will be at least 568 feet (173 m) taller than the Burj Khalifa, which was also designed by Adrian Smith when he was at architectural firm Skidmore, Owings & Merrill (SOM). At SOM, Smith also worked on the design for the Pearl River Tower, while AS+GG also recently won an international competition to design China's Wuhan Greenland Center.

AS+GG says design development of the Kingdom Tower is underway, the foundation drawings are already complete and construction is set to begin 'imminently."

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