Posts filed under Estimation (34)

Media 7 last week featured our very own mistress of stats, Rachel Cunliffe, discussing why you can’t take a monthly cumulative audience and divide by four to get the weekly cumulative audience.

Media 7 host Russell Brown, in his latest Public Address column, looks at how a distinctly dodgy ‘statistic’ that came out of former broadcasting minister Jonathan Coleman’s office to justify Cabinet’s decision not to renew TVNZ 7’s funding was perpetuated through the media …   a must-read.

I’m part of a panel discussion on Media7 tonight (TVNZ7, 9:05pm) on the future of public broadcasting.

We discuss an erroneous weekly cumulative audience statistic which originated from the then broadcasting Minister, Jonathan Coleman: why you just can’t take the monthly cumulative audience and divide by four to get the weekly cumulative audience.

The estimate of 150,000 to 200,000 revellers at the waterfront for Rugby World Cup’s opening night has been dismissed by a statistician who calculated that it was a physically impossible to fit that number in the downtown entertainment areas.

Government and council officials said this week the waterfront was swamped by up to 200,000 people on September 9, leading to crowd control problems and transport failures.

Statistician Tony Cooper, the managing director of research company Double Digit Numerics, found the true figure was probably less than half that number. He estimated a maximum of 70,000 revellers in the lower CBD area.

Read more of this Weekend Herald story (17 Sept 2011) here …

Expect to hear a lot of big numbers thrown about during the Rugby World Cup – and not just about those on the field.

When Auckland hosts the Rugby World Cup Opening Night Celebrations this Friday, people will want to know how many turned up. The success of the event (and justification for the expenditure) will be measured in part by estimated crowd size.

Crowd estimation is often not at all scientific. During tonight’s ONE News bulletin, reporter Jack Tame estimated there were “five or ten thousand delirious Tongan fans”.

How are crowd estimate figures obtained and how reliable are they?

The authors of a new study published in Significance, the magazine of the Royal Statistical Society and the American Statistical Association claim that most crowd estimations are unreliable and that the public should view crowd estimation with scepticism:

“In the absence of any accurate estimation methods, the public are left with a view of the truth coloured 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.

“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.”

Further reading:

• How many were there when it mattered?
• Feeding the Five Thousand – or was it Three?
• The Protest Numbers Game

Also of interest:

• Royal Wedding TV audience closer to 300m than 2bn