涉訟遺囑研究：量化實證、比較法與機器學習

隨著人口高齡化之社會發展，高齡者財產管理越來越重要，而死後遺產分配之問題亦受重視。在此議題上，遺囑既作為遺產分配以及交代後事之方法，其重要性更漸顯在。學界與實務界就遺囑問題雖有諸多著墨，然以量化實證方法研究遺囑問題者並不多見。據此，本論文選擇使用量化實證之研究方法，探討涉訟遺囑之諸問題，並提出法律與事實上之建議。本論文以司法院法學資料檢索系統進行資料蒐集，經篩選後，餘下642則判決，共計670筆遺囑，此後即就法定遺囑要件、非法定遺囑要件中與訴訟要件相關事實、非法定遺囑要件中與遺囑人有關之事實與為非法定要件中與遺囑內容有關之事實進行人工編碼，並呈現單一涉訟遺囑相關事實之研究結果。本論文發現，涉訟遺囑有效比例為78.2%，且代筆遺囑占最大多數（46.7%），其次則為自書遺囑（33.6%）。遺囑人大多為男性（69%），初婚者為最多（28.2%）；遺囑人多於死亡前2年製作遺囑（49.8%），而就遺囑處分類型而言，最多係將遺產分配予繼承人之繼承受益（66.1%），處分標的則以不動產為最多（72.1%），侵害特留分之遺囑則占36.1%。本論文亦發現，52.7%之遺囑人在遺囑製作程序中會尋求專業人士之協助，其中又以公證人為最多（29.4%），其次為律師（19.1%）與地政士（9.3%）。以前述分析結果為基礎，本論文續為檢討我國現行法之遺囑形式要件，並提出自書遺囑要件中「記明年、月、日」之要件在解釋論上應予放寬與應廢除代筆遺囑之建議；另外，本論文發現，涉訟遺囑中出現重男輕女性別偏好之財產分配比例約在1.5%至20%之間，本論文亦建議在進行特留分比例調整時，針對特留分調整幅度之標準及調整原因，應納入包括性別平等考量在內之實證研究；就榮民遺囑涉訟之問題，本論文發現榮民之遺囑被認定為無效之機率高於其他遺囑人，而此應與榮民多透過「代筆遺囑」進行遺產分配有關。本論文之數據顯示，一定程度的法律專業人士參與，對於榮民遺囑有效性確保有所助益，故本論文建議應輔導榮民使用公證遺囑方式處理遺產分配，以避免因遺囑真偽不明而成為訟爭標的；最後，在專業人士參與遺囑製作之問題上，本論文認為應使具有繼承法專業性之律師處理遺囑制定與遺產分配之問題，始能確保其有效性，尤以在社會高齡化之趨勢下，應更具正當性。本論文亦以機器學習之方式，建立遺囑效力預測模型，並探究法院判斷遺囑效力時較為關鍵之因素。本論文發現，在各模型中，準確度最高者為0.7529，其餘分布多在0.6至0.7之間；就準確度最高之模型篩選出之重要特徵則依序為「口授遺囑」、「特留分受侵害之狀態」、「財產分配」、「專業人士參與」與「分配較少原因係該繼承人與遺囑人未聯絡或不孝順」，然其等對於遺囑效力之預測重要性均不高，介於0.6%至1.19%間。

關鍵字

遺囑；實證研究；機器學習；法律資料分析；重男輕女；專業人士

並列摘要

As Taiwan’s population is aging, estate planning becomes more and more important. Among issues in estate planning, wills, which people use to distribute their property after they pass away, are increasingly emphasized. Despite many studies of wills in academia and practice, researchers rarely choose the quantitive empirical method as methodology. This paper adopts a quantitive empirical method to analyze problems of litigated wills and provide legal suggestions based on their findings. Data in this paper are collected from Law and Regulation Retrieving System. After selection, 642 judgments and 670 litigated wills are left. This paper then labeled the data according to statutory facts and non-statutory facts. This paper finds that 78.2% of litigated wills are declared valid and that the most common types are dictated wills (46.7%) and holographic wills (33.6%). Most of the testators are male (69%) and first married (28.2%). 49.8% of testators drafted their wills within 2 years prior to death. As to the content of wills, this paper finds that 66.1% distribute estates among legal heirs, 72.1% contain real estates, and 36.1% violate the legitima portio of a certain heir. This paper also finds that 52.7% of the testators sought help from legal professions while making wills, among which notaries are the most (29.4%), followed by lawyers (19.1%) and land agents (9.3%). Based on the empirical results, this paper further examines the formalities of wills required by the Taiwan Civil Code. It suggests that the requirement of writing down recorded date should be relaxed in holographic wills, and that the dictated wills should be abolished. Moreover, this paper finds that around 1.5% to 20% of litigated will show male preference. This paper also suggests the legal reform on reducing the portion of legitima portio should be cautious since the adjustment of legitima portio might affect gender equality because of patriarchy distribution observed in litigated wills. In terms of veterans, this paper finds that wills made by veterans were more likely to be declared invalid than other people, and this might be correlated to the fact that veterans used to make dictated wills. Thus, this paper proposes that the government advises veterans to choose notarized wills to avoid future disputes. This paper claims that only attorneys with professional training on estate issues are allowed to assist clients’ will-making to ensure the validation of wills. Last, this paper attempts to establish the prediction model of wills validation using machine learning techniques. This paper finds that, the accuracy of models is between 0.6 to 0.7, and the best one is 0.7529. Important factors extracted from the best model are 'oral will', 'violation of legitima portio of a certain heir', 'wills containing property distribution', 'legal professions' involvement in the process of will-making', and 'the reason of certain heir(s) getting less estates is that he(she) was unfilial to the testator'. Neither do any of the factors is absolutely important, since the importance of these factors is between 0.6% to 1.19%.