Chen Xikang, a researcher with the Institute of System Science, Chinese Academy of Sciences, and his colleagues forecasted China's grain and cotton outputs for 2001 with an input-occupancy-output analysis (an extension of classical input-output analysis) invented by themselves. According to the statistics published by the National Bureau of Statistics in 2002, the forecast, precise and world advanced, differed only by 1.4 percent to the results of a sample survey.

The error rate of the grain output forecast in developed countries is between 5 percent and 10 percent. For instance, the error rate for US Department of Agriculture's forecast two months in advance is between 8 percent and 9 percent; former Soviet's error rate is from 7 percent to 8 percent and France's average error in the past six years was 9 percent. Their forecasts generally look no more than two months forward. Chen started to forecast grain output in 1980, six months in advance, and with an average error rate of merely 1.8 percent.

Wassily Leontief, a Noble Prize winner [in economics], put forward the input-output technology in 1973. Cheng and his colleagues brought the factors of occupancy into account and advanced the input-occupancy-output analysis. The factors of occupancy include fixed and floating capital, skilled labor force, knowledge and natural recourse. Knowledge of operational research has also been applied. In April 2001, Chen forecasted that the whole year's grain output would be 459 million tons and cotton output 5.4 million tons, differing by 1.4 percent to the sample survey. The technology leads in theory as well as practice in the world and won the First Degree Award of Science and Technology Advancement of the Chinese Academy of Sciences.

(光明日报 [Guangming Daily] by Xue Dong and Liu Juan, translated by Feng Yikun for china.org.cn, May 10, 2002)