公共建設資金需求龐大，在地方政府財政普遍困窘的情況下，勢必需要透過中央補助，以支應其不足。然而，當各地方皆具有補助需求時，中央反而面臨資金不足分配的難題。因此，行政院經建會推動「跨域加值公共建設財務規劃方案」，期望以自償率門檻審查，要求地方政府將公共建設的外部效益內部化，以提高計畫財務自償性。外部效益內部化的具體策略，包含增額容積、租稅增額財源等，屬於預期性財務規劃，亦即將預期收益納入財務計畫中，作為財政補助的依據，或可視為財政資源分配的籌碼。然而，此一制度亦將衍生各面向的經濟問題亟需思考與解決，首先是中央忽略地方官僚各種自利動機所產生的共有財競爭問題；其次為各種財源籌措工具隱含不確定性所產生的交易成本問題；最後則為地方傾向美化財務效益所造成的道德危機問題。因此，本文建議進行制度調整，面向包含成立資訊共享與協商平台、降低不確定性、置入激勵機制、建立監督管理機制等，藉以預防中央與地方的不一致與衝突，促使地方進行穩健的財務規劃，避免財務缺口之發生，進而才能有效地紓緩政府預算編列負擔。

Under the situation of financial difficulty, local governments confronthuge demand of public funds for infrastructure projects. They need subsidiesfrom the central government. However, the central government also faces theproblem of lacking funds to meet the need of local governments. Therefore, theCouncil for Economic Planning and Development (CEPD) implements “Projectfor Cross-Field Value-Adding in Public Works Financial Planning” to decidethe amount of subsidies through requesting local governments to internalizeexternal benefit and to raise the self-financing ability of project. The specificstrategies include raising the average FAR (floor area ratio), tax incrementfinancing and these expected benefits will bring into the financial plan as thebasis of grant. However, this mechanism will also cause some new economicproblems. First, it neglects the tragedy of the commons. Second, it will arisemore transaction cost which results from uncertainty. Finally, localgovernments may beautify the financial benefits that will result in the moralhazard. Hence, this paper suggests to establish the information sharing andconsultation platform, reduce uncertainty, set up the incentive mechanism and supervision mechanism in order to prevent the conflicts between the local andcentral government, to promote the local governments to do a financialplanning steadily to avoid financial gap and further to relieve the governmentbudget burden.