In this lesson, Lawrence Summers explores two guiding principles for making and then implementing your final decision. The key is to avoid overplaying or underplaying your strategy. Learn how to think at the margin, like an economist.決策過程與實施過程中有兩條指導原則：第一，不要犯不可逆的錯誤；第二，以一種校準的方式來思考問題。關鍵點就是，既不要過度依賴你的策略，也不要思考的不週全。要學會像經濟學家一樣思考邊際這個概念。