災後重建的經濟評估：以九二一震災為例

Economic Appraisal of Reconstruction Decision After Natural Disaster: the Case of 921 Earthquake

天然災害後的重建經常需要政府協助，才能迅速克服困境，然而重建經費龐大，政府如果不能謀而後動，可能不只是浪費國家有限資源而已，更可能耽誤或喪失進一步發展的機會。本文從成本有效性分析、成本效益分析及風險效益分析分別探討九二一震災後台灣的重建成果，屬於「事後」的決策檢討，由於「事後」各種不確定性或客觀條件的約束已經明朗化，所以不能因此而苛責「事前」的決策有誤，但檢討過去有助於改善未來，不只是可以修正決策疏忽之處，也有擴大決策空間之作用。九二一震災的重建決策，基本上是採用成本有效性分析，並以公開招標方式節省預算，但不同行政層級發揮的節約作用有所不同，再且因比價而忽略了重建的效益，不無遺憾。如果能有較寬裕的時間，在重建決策前評審重建效益，讓重建的邊際成本與邊際效益相當，必然有助於提升效率並增進社會福祉。然而，目前災區民眾及決策者似乎仍滿足於恢復舊觀的「重建」目標。重建工作其實也不能忽略風險問題，部份地區（例如谷關向東的橫貫公路）明顯不值得冒險重建，因其再次受災之風險過大，大筆的重建投資可能短期內又化為泡沫，所以災害發生後，也有建言認為應該重視自然復育之功能，但還是經常不敵利益者之壓力，仍然盲目重建。

Government intervention in reconstructions after the outbreak of naturaldisaster is often necessary to recover in a short period of time. Thereconstruction investment is very costly, thus economic evaluation is ofcourse necessary to avoid misallocation of limited resources or delay ofdevelopment opportunities. This paper introduces cost effectiveness analysis,cost benefit analysis, and risk benefit analysis to evaluate governmentdecisions in the reconstructions of 921 earthquakes. It is an ex post appraisalwhich is quite different from ex ante research, because uncertainties and/orconstraints are all clear in the ex post appraisal. However, ex post appraisalis quite useful to future decisions both in avoiding neglects or expanding theoptions of decision-making.The reconstruction decision of 921 earthquakes is basically follow thecost effectiveness analysis in order to save government expenditures.Nevertheless, the cost-saving effects are different among levels ofadministration, and the reconstruction benefits are all neglected ingovernment decisions. If there were enough time to evaluate benefit and toequal marginal cost to marginal benefit of reconstructions, it is obvious thathigher investment efficiency and thus higher social welfare will be availablenow. However, decision makers and local people are seemingly satisfied withthe decision to recover from earthquake as soon as possible. Risk-benefit isanother issue must be emphasized in reconstruction decisions. Somecountry roads in the mountain area are always under the risk naturaldisasters. Large amount of investment may disappear in a short period oftime. Environmentalist emphasizes the importance of natural recovery andthe risk of reconstruction, but final decisions are always subject to the needsof local people, the direct beneficiaries.