知識外溢與都市製造業成長

Knowledge Spillovers and Growth in Urban Manufacturing Industries

新成長理論強調知識外溢效果是造成經濟成長的重要原因之一，而都市是人文薈萃之地，最能展現創新對於都市產業發展的重要性。因此，本文利用台灣都市製造業1991到2001年的資料來檢驗動態聚集經濟（專業化外部性與多樣化外部性）、地方競爭性、以及規模經濟等4種可能產生知識外溢效果管道進行說明，並分別計算對應這些外部性的專業化、分散化、競爭性、以及工廠規模指標。其次，利用動態的都市成長模式與4種外部性作迴歸分析。結果發現，在台灣都市中分類製造業成長當中，專業化與工廠規模扮演負面影響的各有8個產業，而分散化幾乎沒有顯著效果，只有地方競爭性在5個產業中，對都市產業成長具有正面效果。因此建議中小型、不受區位束縛、且處於競爭環境的廠商，對於創新與就業成長最具有正面的幫助。 New growth theory has stressed the role of knowledge spillovers in promoting economic growth. At the same time, such innovations are particularly effective in cities. This paper tries to analyze and examine relative importance of four possible sources of spillovers, including specialization (or MAR externalities), diversity (or Jacobs externalities), competition and plant size through dynamic urban growth model. Based on the analysis of plant-level data of two-digits manufacturing industries in 93 cities between 1991 and 2001, it is found that specialization and plant size both reduce employment growth by 8 industries. Local competition encourages knowledge sharing and growth by 5 industries. In addition, there is little evidence that diversity affects growth. In sum, it is suggested that small-and-medium sized and footloose firms under competitive environment is critical to advance innovation and employment growth.