Legco election opinion polls thrown into confusion

Accuracy questioned as high number of Legco candidates splitting vote mean many are falling within margin of error, making forecasts difficult

PUBLISHED : Thursday, 30 August, 2012, 12:00am
UPDATED : Thursday, 30 August, 2012, 3:36am

The accuracy of public opinion polls in the lead-up to the Legislative Council election is being questioned because of the margin of error and high number of candidates contesting the seats.

Since early this month, the University of Hong Kong's public opinion programme has conducted city-wide, five-day rolling polls tracking support for candidates in the five geographical constituencies and the district council "super seats".

But candidates and academics say the results released each day may not indicate the likely winners because some candidates' support amounts to only a few percentage points, and falls within the margin of error.

For example, in New Territories East - where 13 slates of candidates as well as six individuals are contesting nine seats on September 9 - poll leader "Long Hair" Leung Kwok-hung topped the latest table with 6 per cent.

However, the margin of error of the latest results for this constituency - which saw 614 people interviewed between Friday and Tuesday - could be as high as plus or minus four percentage points.

This means it is statistically possible that any of the candidates could win.

Dr Li Pang-kwong, a political scientist at Lingnan University, said: "Under the proportional representation system, the political parties have split the tickets, trying to win a seat with the fewest votes possible.

"The margin for victory will be very small. The discrepancy could fall within the statistical margin of error."

Candidates and academics also said too many candidates were vying for seats. There are 216 candidates contesting the five geographical constituencies, while 18 candidates are contesting the five "super seats".

Dr Robert Chung Ting-yiu, the director of the HKU programme, which has run rolling polls for Legco elections since 1995, insisted they remained "the best way to gauge the electorate's preferences".

But he admitted the poll could not predict the election result effectively if the margin of victory of the winners over the losers was less than the statistical margin of error.

Chung said the daily sampling of the surveys early this month was at about 250. But it would rise to 650 respondents in the countdown to the election and the results' accuracy would increase.

Chung also said the poll was still relevant and could affect the last-minute strategy of candidates. It was the election system - rather than the ways of conducting the rolling poll - that affected its accuracy, he said.

Ip Kwok-him, caucus convenor of the Beijing-loyalist Democratic Alliance for the Betterment and Progress of Hong Kong, said: "The sampling size of HKU's rolling poll is not large, just around 200 in each geographical constituency.

"Therefore, the margin of error is big and it may not have very significant reference value."

Ronny Tong Ka-wah, who heads a Civic Party slate in New Territories East, said the results were initially less accurate because of the small sampling. But he said the results over the next few weeks could be useful.

Other New Territories East candidates are Ip Wai-ming, Emily Lau Wai-hing, Scarlett Pong Oi-lan, Elizabeth Quat, Raymond Chan Chi-yuen, Yau Wing-kwong, Richard Tsoi Yiu-cheong, Dr Fernando Cheung Chiu-hung, Gary Fan Kwok-wai, James Tien Pei-chun and Wong Sing-chi, Angel Leung On-kay, Raymond Ho Man-kit, Pong Yat-ming, Christine Fong Kwok-shan and Chan Kwok-keung.