立法中的損益權衡之道──法經濟學能為立法者做些什麼

The Trade-off Between Gains and Losses in Legislation-- What Economists Can Do for Legislators

法律經濟分析中最常用，也最為傳統的決策標準，亦即帕累托標準、卡爾多──希克斯標準（財富最大化標準）、羅爾斯標準，各有其運用的範圍與利弊，其中，帕累托標準所需要的信息最少，最為理想，但在實際生活中往往難以達成；卡爾多──希克斯標準要求比較受益者的收益與受損者的損失，當兩者可比時，它總能判斷法案是否值得實施，並且選擇效率優先的方案；但它相對忽視了權利的保護和弱勢群體的保障問題；羅爾斯標準對弱勢群體保障力度相對最大，但它在促進效率方面具有相當的缺陷。立法者應當在這三種標準中進行有效的抉擇，這種選擇可以用一個分為兩層次的模型來加以概括──在保障基本生活底線的情況下，應當儘量追求帕累托改進和帶有充分補償的卡爾多──希克斯改進，在此基礎之上進行成本收益分析，通過並實施那些確能帶來更高預期收益的法案，在開放立法和審議民主的前提下，法經濟學家可以對立法中的權衡損益作出專業的成本收益評估，從而作出有建設性的貢獻。

The most traditional and most widely used decision criteria in economic analysis of law are Pareto criterion, Kaldor-Hicks criterion and Rawls criterion, which respectively have their advantages and disadvantages and scopes for application. Pareto criterion needs the least information and can get most idealized results, but is unattainable in real life. Kaldor-Hicks criterion requires the comparison of benefits of beneficiaries and losses of sufferers. If the comparison can be made, it can always determine whether a proposed law should be implemented and choose the most efficient project. However, this criterion neglects the protection of rights and social security for the disadvantaged groups to some extent. Rawls criterion gives most powerful protection for the disadvantaged groups, but has defects in improving efficiency. The legislators must choose their standard among these three criteria, which can be summarized with in a two-level model. With a guaranteed bottom line of welfare, legislators should pursue Pareto improvements and Kaldor-Hicks improvements with sufficient compensation. On this basis, cost-benefits analysis can be made to discover the laws with more expected benefits. With legislation open to the people and deliberative democracy, economists can give professional assessments for the gains and losses of a particular law and make more contributions for legislation.