This is a stark example of how bad academic studies can be.
The study's foundation for the "false conviction" rate is based upon a well known, misleading database from the anti death penalty organization, Death Penalty Information Center (DPIC) (1).
This misinformation has fueled a significant fraud by the anti death penalty movement, which they have exploited for over 15 years (2).
The DPIC redefines "exoneration" and "innocent" in the same manner as if they had redefined lie as truth.
The DPIC's lies regarding this list are numerous and ongoing (2).
The DPIC's foundation for "exonerated" and "innocent" is so poor that not one case need have any evidence for actual innocence for the DPIC to call them exonerated and/or innocent (3).
It is hard to imagine how Gross et al could not know this, from both basic fact checking, as well as from the publicity of this problem within the public square.
By a number of reviews, it appears that the DPIC "innocent" claims are from 70-83% in error (4), meaning that the 117 or 107 numbers, from Gross et al, are really 27 or 25, using an average 77% error rate.
This would lower the statistically projected actual innocent conviction error rate down from the 4.1% to 0.9%, using that average 77% error.
False or unproven claims for "innocence" or "exoneration", of those sentenced to death, have been an anti death penalty standard for decades, as today (4).
1) From the study by Gross et al:
"Data. We examine exonerations among defendants sentenced to death from the beginning of the “modern” death penalty in the United States in 1973, after the Supreme Court invalidated all prior death sentencing laws (11), through the end of 2004. Our data come from two sources.
(i) Death sentences since 1973 are tracked by the Bureau of Justice Statistics (BJS) . . . ."
(ii) The Death Penalty Information Center maintains a list of defendants who were sentenced to death in the United States and exonerated since the beginning of 1973 (13), including 117 who were sentenced to death after January 1, 1973 and exonerated by legal proceedings that began before the end of 2004.
We collected additional data on these cases from public records and media sources, expanding on the dataset used by Gross and O’Brien (7). We were able to match on several key variables 108 of the 117 death sentence exonerations in this period to specific cases in the BJS database to produce the database we analyzed.
Footnote 13. Death Penalty Information Center (2013) The Innocence List. Available at www.deathpenaltyinfo.org/innocence-list-those-freed-death-row . Accessed January 6, 2013."\
2) This is a look at how well destroyed the DPIC's "EXONERATED" and/or "INNOCENTS" list is and how it has been so deceptively used by the anti death penalty movement. Richard Dieter, the former head of the DPIC and architect of this deception, participates.
The "Innocent", the "Exonerated" and Death Row:
An Open Fraud in the Death Penalty Debate: How Death Penalty Opponents Lie
"For Inclusion on DPIC's Innocence List
"Defendants must have been convicted, sentenced to death and subsequently either-
a. Been acquitted of all charges related to the crime that placed them on death row, or
c. Been granted a complete pardon based on evidence of innocence."
from link at Gross et al Footnote 13, just above
Note from Sharp: All of the cases could be from 2a & b and have zero evidence for actual innocence and be called "innocent" and/or "exonerated" based upon the DPIC's intentional and false redefinition of those well known words, as is known from basic fact checking and/or the extensive reviews of this problem in the public square.
President Nixon, the most famous pardon, was, legally and actually guilty.
See also, Lena Baker, a Georgia post execution pardon, based upon racism, at trial, even though there was no dispute she committed the killing, now, judged as manslaughter, not a capital murder, based upon Ms. Baker's claims. "The Parole Board did not find Lena Baker innocent of the crime. The Board concluded that it was a grievous error to deny clemency in 1945 to Ms. Baker, and this case called out for mercy." see page 18,
Sharp: I am not sure, if this pardon is, only, based upon Baker's claims why she was not fully pardoned, based upon her actual innocence, as her claims were based upon self defense. It appears what the Parole Board, really, did was to base their decision upon the reality that, factually, they can't know what really happened, with the actual killing, but that the trial was so egregious, that justice demanded her pardon, as a matter of mercy. I have not researched this case, but, based only upon the known public information, this was a declaration based upon mercy, if not justice.
4) See Sections 3 and 4 within