Budget Act Article 34

With respect to major public construction projects and major policy implementation plans, before the budget estimates and budget proposals are compiled, a cost efficiency analysis report on the alternative measures and substitute measures must be first drawn up and attached with an explanation of the financing and capital employment, and the report should be forwarded to the Legislative Yuan for its files and reference.
中文原文 預算法第34條
重要公共工程建設及重大施政計畫,應先行製作選擇方案及替代方案之成本效益分析報告,並提供財源籌措及資金運用之說明,始得編列概算及預算案,並送立法院備查。

English translation for reference only; the Chinese text prevails. Not legal advice.