二十一世紀以來的國際發展援助議程益加強調援助有效性，如何確立援助過程中最後階段—政策到發展結果—的有效性，則與2015年 2019年與2021年諾貝爾經濟學獎得主，使用個體資料、應用因果推論方法、進行反事實分析緊密相關。本文回顧援助有效性的背景，介紹反事實分析的邏輯、方法，並透過訪談與文獻分析，檢視臺灣目前政府開發援助中，已獲學術期刊審查刊登的反事實分析案例，包括國際合作發展基金會在南太平洋島國吉里巴斯與馬紹爾群島的園藝計畫以及海地之糧食安全計畫。本文發現上述案例突破過去臺灣援外工作純質化敘述、可能流於主觀的評估方式，除具體呈現援助成效並予以量化，亦有助於國內外了解臺灣的發展援助工作，打破金援外交等負面刻板印象。未來建議將事後評核思維完整納入計畫初期準備與評估階段，收集基線資料，擴大樣本數，更積極與相關發展議題的文獻對話，並與其他國際發展組織交流，以期進行更完善嚴謹之成效評估。

Since the beginning of the twenty-first century, the international development agendas have put more emphases on aid effectiveness. How to ensure the effectiveness from policies to development outcomes, the last stage of the aid process, is closely related to counterfactual analyses using micro-level data and causal inference techniques, recognized by Nobel Memorial Prizes in economics in 2015, 2019, and 2021. This paper reviews the background of aid effectiveness, introduces the logic and techniques of counterfactual analyses commonly used in development studies, and examines academic publications applying counterfactual analyses to evaluate Taiwan’s official development assistance (ODA) projects. These include three projects carried out by the International Cooperation and Development Fund (TaiwanICDF), namely horticulture projects in Kiribati and the Marshall Islands, two Small Island Developing States, and a food security project in Haiti. These evaluation studies go beyond the past practices of purely qualitative and descriptive evaluations of Taiwan’s ODA, which may suffer from being subjective. Counterfactual evaluations present and quantify TaiwanICDF’s aid effectiveness, increase the public’s understanding of Taiwan’s development aid and refute the negative stereotype of checkbook diplomacy. To conduct more rigorous impact evaluations, this paper suggests incorporating the evaluation design into the early stage of initial preparation to collect baseline data, increasing the number of observations and engaging in more interactions with other international development organizations.