司法或正義？法官對減刑條例的判刑變化

Abstract

台灣於2007年通過《中華民國九十六年罪犯減刑條例》，要求法官在宣告刑罰時對於2007年4月24日之前犯下的罪行減半刑期。本研究透過斷點迴歸設計探討台灣法官在該條例實施前後的判刑行為差異。本研究發現，該條例為法官帶來一個兩難的困境，使得法官在判刑時需要遵守的「比例原則」和「正義原則」之間產生衝突。該條例生效後，法官對適用該條例的罪行增加了平均約43.29天（增加了24.7%），對不適用該條例的罪行則減少了平均約18.26天（減少了12.5%）。此判刑行為的改變可能源於法官為了平衡「比例原則」和「正義原則」而做出的雙重妥協。法官增加刑期的行為可能是為了減少減刑後刑罰與原先刑罰之間的差異所帶來的效用減損，原先刑罰可能被視為最佳並作為參考依據；法官減少刑期的行為則可能是為了減少適用和不適用該條例的罪行之間刑期差異所引起的效用減損。本研究提供了證據支持法官在「比例原則」和「正義原則」之間尋求平衡的假設，並發現法官同時對適用該條例的犯人「增加刑期」和不適用該條例的犯人「減少刑期」的行為。進一步使用事件研究法分析後，發現這種效果至少持續了半年。最後，本研究還發現法官的「增加刑期」和「減少刑期」行為與其所在法院的法官平均判刑程度有關，顯示法官之間可能存在「同儕效應」。

We estimate judges’ responses to Taiwan’s 2007 Criminal Commutation Act that requires a reduction in sentences by half for crimes committed prior to April 24, 2007. Using an RD design, we find that, after the Commutation Act was put into effect on July 16, judges immediately increased the sentences by around 43.29 days (24.7 percent) for thefts committed before April 24 (sentence aggravation), and decreased the sentences by around 18.26 days (12.5 percent) for those committed after that day (sentence mitigation) – a double compromise on the proportionality principle of law. Judges practiced the sentence aggravation probably for reducing the disutility caused by the deviation of the commuted sentences from the pre-commutation sentences, which were anchored by judges as optimal and set as a reference point. Judges practiced the sentence mitigation for the ineligible offenders likely for minimizing the disutility caused by the disparity between the sentences eventually served by the eligible and ineligible offenders. Finally, we present suggestive evidence to support the hypothesis that both practices coexisted because judges were seeking a balance between the justice principle and proportionality principle after the Act created a conflict between them.