China's official statistics are in line with global standards but the way they are compiled and presented need to be improved to catch up with rapid economic and social changes, said a top statistician of the United Nations (UN).

"The way to do that is to update the methodology, to be as transparent as possible, put the numbers in context and let people access them," Paul Cheung, director of the statistics division of the UN Department of Economic and Social Affairs, told reporters.

"Chinese official statistics have improved a lot through the years, in coming up with the numbers to help the government understand the very major profound changes in the Chinese economy. It's not perfect but it's evolving," Cheung said ahead of the first World Statistics Day, which fell on Wednesday. The UN and Chinese government jointly celebrated the event at the UN Pavilion of the Shanghai Expo.

Referring to the country's statistical reform on housing statistics, Cheung said decision-makers should consider the economic value of compiling housing vacancy statistics, given that it is very difficult to collect such information to measure the tightness of the housing market.

"It's not the most critical of economic indicators. I was a bit of surprised why so much attention now in China has been paid to this particular indicator," said Cheung, adding that the attention on this indicator was not motivated by economic professionals.

Focusing on the housing vacancy rate does not help with the understanding of the housing supply-demand imbalance problem, he said.

China is conducting pilot programs in some cities on housing vacancy statistics to help measure the vacancy rate, Ma Jiantang, head of the National Bureau of Statistics (NBS), said in early September.

"We should utilize the census data to collate information on vacant houses," Ma said, adding that nearly 10 percent of the census respondents will be asked to fill in a questionnaire on residence information.

Despite the various definitions of "vacant housing" and the unwillingness of some residents to provide genuine information, the government will try to collect such statistics in an accurate and professional manner, he said.

Ma also said the government will take steps to improve the accuracy and credibility of its data.

The NBS has come under fire in recent years for its figures on housing, income and consumption. The discrepancies between official figures and people's perceptions were intensified after the bureau said China's average home prices rose 1.5 percent for the whole of last year. Observers and many people said the actual growth could be much higher than the official rate.

Ma expected a draft of the housing price statistics reform to come into effect from 2011.

"China is not the only country having problems on housing statistics. The housing market is not a homogeneous market, with different types of houses and different price trend for each type of houses," Cheung said.

"I would produce as many housing statistics for different type of houses as possible. And (the bureau should) explain to the public how the numbers have been collected and the methodology used."

That is especially difficult for China, a big country with diverse housing markets and various price movements, he said.

The NBS is also planning to revamp the indexes that have raised public concern. It will adopt unified standards and elevate the methodology used for calculations, said Ma.