都市特徵與動態外部效果對都市成長與產業發展的實証分析

Abstract

本研究的主要目的，是實証分析城市內與產業間的兩種外部效果對都市成長的影響。以台灣地區1976年、1986年與1996年的21縣市資料，探討不同類型的外部效果與都市特徵，對都市與產業成長的影響。實證結果顯示：(1)都市內產業別的就業成長與都市內產業別的起始就業量成反向相關；(2)都市內產業別的就業成長與起始年的產業內相互競爭水準成正向相關；(3)都市內產業別的就業成長與起始年的都市內產業多樣化程度成正向關係。都市內產業的多樣化程度對就業成長的影響，相對的比其他影響效果為大。除此之外，(1)城市內產業別的工資成長率，與城市內產業別的起始工資水準呈負向關係；(2)城市內產業別的工資成長率，與起始年的城市內產業的多樣化水準成正向關係。整體而言，實證結果顯示，城市內的產業競爭與產業多樣化都有助於就業與工資的成長；相反的，都市內產業專業化對就業與工資的成長有負面的影響。此研究結果與Jocobs的理論一致：產業間交叉的外部效果與相互競爭，比產業內的外溢效果更有助於產業的成長。

The purpose of this paper is to investigate the influences of citywide and city-industry externalities on city growth. The effects of various externalities on city and industry growth for two different time periods in Taiwan are studied. The results indicate that employment growth at the city-industry level is: (1) negatively related to the initial city-industry employment; (2) positively related to the level of competition in the initial year; and (3) positively related to the degree of diversity in the initial year. The extent of the impact of the diversity externality is relatively large compared with the other effects. In addition, wage growth at the city-industry level is found to be: (1) negatively related to the initial city-industry wage rate; and (2) positively related to the degree of diversity in the initial year. Overall, we find that specialization hurts, competition helps, and city diversity helps both employment growth and wage growth. Our results favor Jacobs`s theory, which would suggest that cross-industry externalities and local competition are more important for industry growth than are intra-industry spillovers.