Every five days, Guo Shufang, a 48-year-old retiree, would spend three hours visiting the Binjiang Department Store in Tianjin's hustling business district.

Rather than hunting for bargains, Guo, a part-time statistician in Tianjin, would ask the salespeople downtown for the prices of more than 60 kinds of cloth. She would then spend the next day typing into her computer all the rates, which would then be sent to the National Bureau of Statistics, which will then compile data for the latest economic indicators such as the consumer price index.

Guo is one of the 3,000 statisticians scattered across more than 550 cities and towns in the nation. Whether this legion of statisticians could come up with the figures that accurately reflect the economic trend is increasingly important for the nation's top decision-makers for working out macro economic policies and analysts.

Vice-Premier Li Keqiang said in January that statistical work is particularly important at the moment, as accurate figures are vital in making accurate and timely moves to cope with the ongoing financial crisis.

"We are facing increasing change now," Ma Jiantang, head of the statistics bureau, said at a conference. "The requirements for the accuracy and reliability of our statistics are rising much faster these days."

Over the past month, the public cast doubts over data about the average salary of urban employees compiled by the bureau. The official figure amounted to 7,399 yuan for the first quarter, which many complained online was far above their income level.

The statistics bureau later said that due to rising income disparity, the average income was far above the median income level of wage earners.

Meanwhile, the figure was calculated based on sample workers from State-owned enterprises and joint venture enterprises, but excluded employees from private enterprises, which only accounted for a very small proportion of the total labor force when the figure was initially complied. However, that approach tended to overstate the figure, as the salary level in private enterprises was usually lower.

Ma said the bureau would continue to improve its statistical approach in the coming years and make them better reflect the change in the economic structure.

The statistics bureau also faces increasing scrutiny from overseas analysts. For example, the International Energy Agency had questioned the reliability of China's economic data in its report on the global oil market released on May 14, saying the first quarter GDP growth didn't tally with falling oil demand, Dow Jones reported.

The statistics bureau later explained on its website that the mismatch was largely due to the faster contraction of energy-intensive sectors while it was a mistake to oversimplify the correlation between economic growth and energy use.

"My personal experience is that the statistics from the NBS is reliable," said Li Lianyou, a professor from Central University of Finance and Economics.