Abstract: The growth of cargo throughput isclosely relevant to economic development level. Based on ridge regression,totally 6 economic influence factors, including light/heavy industry productionvalue, total value of imports/exports, GDP, and capital investment, areanalyzed and compared with their influences upon the cargo throughput of Tianjin Port,Shanghai Portand Guangzhou Port from 1990 to 2005 in this paper. The results show that the economicfactors affect the cargo throughput dissimilarly among different ports: thesame factor produces different influence on cargo throughput; furthermore, theinfluence factors belonging to the same economic type also produce quitedifferent influences on cargo throughput. Among the 6 economic influencefactors, light industryproduction value, total exports and total imports respectively producesthe greatest influence on cargo throughput of TianjinPort, ShanghaiPort and Guangzhou Port.

Key Words: Throughput; Influence factors;Differences; Ridge Regression   

1.Introduction 

Port isan important gateway of foreign trade, and itscargo throughput can reveal the local tradeand economy level. Figure 1 shows the relativity of annual growth rate between cargothroughput of Shanghai Port and total value ofimports and exports, gross domestic product and industry production value. Thecurves have similar development tendency. It is mainly because that thedevelopment of industry and economy promotes foreign trade, and the foreign tradecreates more cargo throughput again. Conversely, the expansion and developmentof port produces more development opportunities for industry and trade, andtherewithal advances the local economy (Xu Jianhua 2007). Therefore, the localeconomic development is very crucial for the port’s development, and the port’scargo throughput also directly reflects the changes in economy and foreign trade.

Because of such a strong relativity,many professionals adopted regression method to forecast port’s cargo throughput(HuangRong-fu 2004; Deng Chaofeng 2006). However,both the comparability of economic indicators impacting different ports’ cargothroughput, and the suitability of explanatory variables used in regression modelshave not been approved. Liu Bin, Zhao Yichuan, Chen Yong (2002) and Xu Jianhua(2007) analyzed the influences on a port’s cargo throughput imposed by several economicindicators, but they didn’t further apply them to other.