The Hong Kong 7/1 March: Crowd Size Estimates (Hong Kong Police)
SOURCE #2: HONG KONG POLICE says 200,000
[translation] Hong Kong Police Public Relations Department Chief Inspector Szema Wei-lu said that their figures are for internal reference only and they will not disclose their method of calculation. He emphasized that the tail end of the march left Victoria Park around 530pm. They have already considered that there are a few more citizens who came after that in addition to considering those who joined the march in the middle. He says that the police estimate is reliable.
警察公共關係科總警司馬維騄昨以數據只作內部參考為由，不公開統計方法，但強調警方於遊行隊伍「龍尾」在5.30分左右離開維園截算，其後在「龍尾」加入的市民不多，並已考慮沿途加入的人數，雖有誤差，警方的數據仍可信。(
(SCMP) Police taught us how to count, say organisers. July 3, 2004.
Organisers of the July 1 rally yesterday said that their estimate of 530,000 for the march's turnout was based on a counting method learned from the police. The police, who gave an estimate of 200,000, declined to be drawn on why there was a gap of 330,000 between their figure and that of the organisers."The method we used was suggested by the police, who shared their experiences with us," said Hong Kong Christian Institution director Rose Wu Lo-sai, one of the organisers.
"The police told us that when people cover Victoria Park and the entire [route] from Causeway Bay to Central, then there should be about 170,000 people."
Ms Wu said the first group of marchers set off at 2.30pm and reached the Central Government Offices at 4pm. The last wave of people arrived at the offices between 7.30pm and 8pm.
"We applied the time it took the first group to reach Central Government Offices and the time of arrival of the last group to calculate that there were about three groups of 170,000," Ms Wu said. "We then added 20,000 to account for the extra half-hour and the people who left before reaching Government House."
A police spokesman said their figure of 200,000 was not an official head count but an estimate for internal use for crowd control purposes. It is understood police arrived at their figure using several calculation methods, including counting the number of people walking past a given area within a certain period of time and multiplying the figure by the duration of the march.
Fellow march organiser Wu Chi-wai said a second method used to determine the figure put the crowd at 300,000. This involved placing four people in different areas of Wan Chai to count the marchers passing by for five minutes in each of four hours. "We felt this would reflect less than the actual number of people because it did not take into account the people who joined in later on," Mr Wu said.
Ah! Here we have the explanation of what the organizers did with the counts obtained by volunteers at various points --- they ignored them because they 'felt' it was a low number. This is unethical, but then politicians don't have to abide by any professional code for statisticians.
From that report, it seems that no one has caught on to the fact that it was physically impossible to fit three groups of 170,000 people within the stated time frame. The additional piece of information in this article is that the last wave of people arrived between 730pm and 800pm. If the traffic after 730pm was negligible, then there was only 2-1/3 groups for a total of 2.33 x 170,000 = 396,000.
The police did not disclose their method. The following extract from a newspaper article may be the best approximation to the methodology behind the police estimate. However, I cannot be 100% sure that this is it.
(Tai Kung Po) Was it an olive branch or an unsheathed sword? By Mei Ying. July 6, 2004.
The authoritative person made these calculations: the distance from the Central Government Office to Victoria Park was 5.2 kilometers. The marchers formed eight people per row, or 16 people for every two rows; people are about 30 to 40 centimeters apart; each square meter of the roadway can accommodate 32 people; if the roadway was full, there would be 160,000 persons. But the weather was hot and people were further apart than usual. About one half or one third of the march was less dense. "Long Hair" stood under the Goose Neck Bridge to put on a show that created congestion in order for the media to take films to show the dense crowd. But for the whole trip, it would be lucky if there were 120,000 to 130,000 marchers. When the march leaders reached the Central Government Office, two of the six soccer fields were already empty. Because the weather was hot, many people used umbrellas and fanned themselves. So each soccer field was likely to have only about 6,000 to 7,000 standees. Therefore, the number of people at the rear of the march was at most 30,000. Thus, the police estimated that the total number of marchers from the head of the march to the tail of the march was 160,000. They then overestimated by adding another 20% in order to make sure that they have enough police resources to maintain public order and safety. Thus, they made the public estimate of 200,000.
權威人士還作了如下計算：從政府總部到維多利亞公園全長約五點二公里。遊行隊伍一排八人，兩排十六人；人距約三十至四十公分，一平方公尺路段內最多只能容下三十二人行進：全程人滿約十六萬人行進。鑑於天氣熱，人距大，約有一半到三分一路段人流疏鬆，儘管「長毛」鵝頸橋下站台演說，造成一段人流擁擠，似意在給傳媒拍攝出遊行隊伍擁擠之效果。但全程觀之，全程實際人數約有十二、三萬就算不錯。當龍頭抵政府總部，龍尾的維多利亞六個球場有兩個大部分空置。天氣炎熱，打傘者眾，普遍搖扇，每個球場只能站六、七千人，龍尾的四個多球場約有三萬之眾。估計警方從龍頭到龍尾以總數十六萬人計，再加上以百分之二十的比例高估，以便布置較充分警力維持治安，便作出遊行人數約二十萬之公開評估。