公共基礎建設對廠商生產力的影響：以921地震的自然試驗為例

The Impact of Infrastructure on Plant Productivity: Evidence from a Natural Experiment of the 921 Earthquake

公共基礎建設在經濟發展中所扮演之角色向來皆是各國政府所關注的議題，雖然過去已有許多文獻探討其與私部門生產力兩者之間的關聯性，但鮮少研究利用廠商層級資料並以自然試驗之機制來探討其因果關係。有鑑於此，本研究運用1998年至2003年工廠校正暨營運調查的追蹤資料進行分析，藉由921地震對各區域公共基礎建設產生不同程度之衝擊的這個自然試驗，佐以相關計量模型來估計公共基礎建設對廠商生產力的影響。經實證估計後本研究發現，當前一期之公共基礎建設支出（以各區域交通及其他經濟支出衡量）上升1%時，廠商的總要素生產力將會提升0.06%左右，且高生產力廠商對於公共基礎建設的影響效果會更為明顯，而此結果將可作為日後政府在進行公共建設投資時在效益評估時的參考方針。關鍵詞：生產力、公共基礎建設、自然試驗

The role of infrastructure in economic development is always a concern for any government. Despite the growing literature devoted to the correlation between infrastructure and productivity, there is still little plant-level evidence via their causal relationship by employing a natural experiment design. Consequently, in this paper we utilize plant-level data between 1998 and 2003 and employ several econometric models to investigate the causal effects of infrastructure on plant productivity, using the 921 earthquake in Taiwan as a natural experiment. Our results show that a 1% increase in a previous year’s infrastructure expenditure in each city (measured by the expenditure of transportation and other economic services) raises the total factor productivity of each plant located in that city by 0.06% during the present year. Furthermore, this impact is larger for plants with higher total factor productivity compared to those with lower total factor productivity. Our results are expected to have important implications for the benefit measurement of public infrastructure investment policy.