不为任何立场，只是想正确的把事情弄清楚。
我把你给的参考资料都看了，
也看了一些参考资料引用的原始论文，
首先看原文:
※ 引述《jeanvanjohn (尚市长)》之铭言：
: ※ 引述《hoshi1992 (YAYAUUU)》之铭言：
: : 为了避免那99%的真正的杀人犯被放出来再作案
: : (假释or之类的)
: : 1%冤死的是能接受的代价
: : 阿可是阿
: : 干这1%又不是你，凭什么决定他们要被牺牲阿
: : 完全是一种别人的孩子死不完的概念
: : 这就是反废死最机掰的地方啦
: 那反过来说，杀人犯被放出来有3%机率再杀人，那3%冤死是不是就是可接受的代价?
^^^^^^^^^^^^
这个3%的来源是我想探究的地方，因为我以前从没看过这么笃定的数字
: 不好意思，废死联盟的人认为，"和误判相比，这样的3%是可以接受的":
引用1: http://www.fhl.net/2000/death_issue/issue3-5.htm
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
这个引用是陈文珊的文章，文章中跟 3% 这个数字有关的文字如下:
1972年533位死囚经富尔曼(Furman)最高法院改判后，监禁或假释出狱的人中只有六人再
次 犯下谋杀案。
也就是说 再犯率应为 6/533 = 1.多%，但后来原PO说陈文珊的文章有欺骗之嫌，
所以又在推文中补了两个参考资料。
================================================================
引用2.The Case Against The Death Penalty by Hugo Adam Bedau
http://users.rcn.com/mwood/deathpen.html
姑且不论该文章引用各种资料和文献后，
最后的结论是支持废死，我们来看看关于1972年这个案件:
这个文章在Deterrence单元中的第三个小单元中提到:
A recent study examined the prison and post-release records of 533 prisoners
on death row in 1972 whose sentences were reduced to life by the Supreme
Court's ruling in Furman. The research showed that 6 had committed another
murder. But the same study showed that in 4 other cases, an innocent man had
been sentenced to death.(16)
简单来说就是 再犯率 6/533 和陈文珊的文章内容是一样的，
另外后面的意思好像是指说有4个犯人是被无辜判死。(有错欢迎更正)
引用3.A National Study of the Furman-Commuted Inmates: Assessing the Threat to Society from
Capital Offenders by James W. Marquart & Jonathan R. Sorensen
http://tinyurl.com/obn22r5
好的，这篇就是引用2中上面那段最后(16)的那篇论文，
在论文最后conclusions中提到:
While there is some ambiguity as to just how many death row prisoners were actually affected by Furman, the research reported here accounts
for 558 inmates scattered across twenty-nine states and the District of Columbia.91 We tracked these 558 prisoners' institutional and
release behavior for nearly fifteen years. In the prison setting, these prisoners committed six murders-killing four prisoners and two correctional
officers. However, the majority of the former death row prisoners served out their sentences with few instances of serious
institutional misconduct. A minority were responsible for the bulk of disciplinary
infractions.
Over the course of fifteen years, 239 Furman-commuted prisoners were released to the free community. These parolees have spent an average
of five years in society. Twenty-one percent recidivated and were returned to prison, 12% committing new felonies.94 Only one parolee
from Texas committed a second homicide. On the other hand, nearly 80% of those released to the free society have not, at least officially,
committed additional crimes.
也就是说，558人中，在监狱中杀了4个囚犯和2个惩教官员，
而真正放出来的犯人239名只有一个假释者犯下第二次杀人罪行，
以下是原PO贴了以上引用之后的叙述:
重点是，这份报告是废盟也认可的报告。
1972年，有558名被判死刑的犯人因为美国最高法院对死刑的判定标准改变而免死，
其中315人(含死在狱中以及逃狱被抓者)未出监，实际出监者243人。
在243人中，再犯各种罪行的是52人(21%)，其中再犯谋杀的是7人，
所以确切的数字是2.8%。
也就是说，死刑犯被假释出狱后，有3%的机率再犯杀人罪。
这是美国以及废死联盟也认可的数据。
===============================================================
怎么算都不是这个数据，此外这篇论文最后来提到:
H.L.A. Hart asked: "What is the weight and character of the evidence that the
death penalty is required for the protection of society?" This question, in
our opinion, is the most salient one in any discussion of the utility of
capital punishment. Seven (1.3%) Furman-commuted prisoners were responsible
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
for seven additional murders. Certainly execution of all 558 prisoners would
have prevented these killings. However, such a "preemptive strike" would not
have greatly protected society. In addition, four innocent prisoners would
have been put to death. The question then becomes whether saving the lives of
the seven victims was worth the execution of four innocent inmates.
The data in this paper suggest that these prisoners did not represent a
significant threat to society. Most have performed well in the prison; those
few who have committed additional violent acts are indistinguishable from
those who have not. Therefore, over-prediction of secondary violence is
indicated. More than two-thirds of the Furman inmates, using a very liberal
definition of violence, were false positives-predicted to be violent but were
not. We cannot conclude from these data that their execution would have protected or benefitted society.
也就是说588人最后再犯下杀人案件的有7人，然后被误判的有4人，
论文最后的观点是对死刑抱持怀疑的态度，认为死刑未必能够作为保护或使社会受益。
排版不好请见谅 (_._)

简单来说 就是尚市长不是算错就是伪造数据呵