Thursday, July 15, 2010

On The Rate of Wrongful Conviction: Chapter 0.5

In my spare time, I'm preparing a compilation of essays on various estimates of our country's wrongful conviction rate.  As I draft them, I'll publish them here. When I'm done with all of them, I'll compile them into a single document and make it available on Scribd for free, and on Amazon for a minimal cost.

The chapters will be numbered according to the predicted wrongful conviction rate, in percent. I began with the lowest estimate of 0.027%, and I am working my way up to the highest. Keep in mind that we have a lot of people incarcerated, around 2.5 million. That means a wrongful conviction rate of only 1%, if applicable to all those incarcerated, means we have wrongfully imprisoned 25,000 people. A wrongful conviction rate of 10%, if applied to all those incarcerated, would mean we currently have a quarter million people incarcerated for crimes they did not commit.

I didn't pull the 10% number out of thin error air. We'll soon be talking about estimates that exceed 10%. For now, it's time to look at the Huff number.

Chapter 0.5
The Huff Number

Twenty years before Oregon Prosecutor Joshua Marquis wowed Justice Scalia with his 0.027 percent wrongful conviction rate estimate, Ronald Huff bothered to ask 53 Ohio prosecutors what they thought the wrongful conviction rate might be. He also asked 55 Ohio county judges, 59 Ohio sheriffs and chiefs of police, and 21 Ohio public defenders. In addition, he asked 41 state attorney generals from across the U.S.

Huff didn’t just guess at a number, as Joshua Marquis would do twenty years later. Huff asked other people to guess for him. He asked each of his survey participants to select one of four answers:
     Less than 1%
     1 to 5%
     6 to 10%

Seventy-two percent of the respondents selected less than 1 percent but greater than zero. Twenty percent guessed somewhere between 1 and 5 percent. Only two percent of the respondents felt the number was greater than 5%.

Astonishingly, six percent of the respondents indicated their belief that innocent people are never convicted. Judge Learned Hand would be proud.

Huff distilled the results into a single number of 0.5 percent.
With these figures before us … we decided to see what the magnitude of the problem would appear to be if we cut the 1% figure in half, on the grounds that most of the respondents selected the category “less than 1%,” thereby indicating that they believed wrongful conviction does occur (they rejected “never”), but also indicating that it occurs in less than 1% of all felony convictions. Given that the midpoint between zero and 1% is 0.5%, we felt justified in using that figure.

We are left with what appears to be an impressive figure for accuracy and justice: 99.5% of all guilty verdicts in felony cases are handed down on people who did indeed commit the crimes of which they have been accused. But in terms of real numbers, this figure is more disheartening. According to the U.S. Department of Justice’s Bureau of Justice Statistics … the estimated total number of persons arrested and charged with index crimes in 1993 was 2,848,400. [Index crimes are murder, non-negligent manslaughter, forcible rape, aggravated assault, robbery, burglary, larceny theft, motor vehicle theft and arson.] Conviction rates vary from state to state and by type of offense, but based on the best available data, an analysis of the likelihood of felony conviction in the nation’s 75 largest counties, we can reasonably assume about 70% of all felony arrests result in conviction. … Now, if we go to our survey data and to the study of the American jury, and assume that 70% of those arrested for index crimes are convicted, this would yield the following estimate of wrongful conviction for the eight crimes in the FBI index only:

1990 arrests for index crimes                              2,848,400
    x conviction rate (70%)                                          x 0.7
1990 convictions for index crimes                        1,993,880
    x wrongful conviction rate (0.5%)                          x .005
Estimated number of wrongful convictions                  9,969

Thus, if these apparently conservative estimates are reasonable, we are facing an interesting dilemma: A high volume of prosecutions, even if 99.5% accurate when guilty verdicts are rendered, can still generate about 10,000 erroneous convictions for index crimes in a single year. And this figure does not including [sic] the many erroneous convictions that occur in cases involving crimes not in the index; when these are added to the 10,000 “index false positives,” the result is even more sobering.
Huff was a pioneer. He was the first to make an effort to quantify the rate of wrongful conviction. His number though is probably low, for several reasons.

First, Huff’s sample was dominated by police, prosecutors, and judges, all of whom are loath to admit that those in their profession may be putting innocent people in jail. Only nine percent of the respondents were public defenders. Huff himself recognized this problem.

Second, Huff was ambiguous about whether the respondents were to assess the wrongful conviction rate within their own district or for the U.S. as a whole. Later surveys, to be discussed soon, will show that police, prosecutors, and judges consistently perceive their district to have lower wrongful conviction rates than the rest of the country. It’s the Lake Wobegon phenomenon, where every child is above average.

Third, Huff conducted his survey when use of DNA was still in its infancy, and I do mean infancy. In 1986, the same year Huff initially published his results, DNA testing was used for the first time in the case of Pennsylvania v. Pestinikas, a civil case involving allegations of switching body parts at a funeral home.

Later surveys similar to that conducted by Huff will show that the spate of DNA exonerations cause respondents to significantly increase their estimate of the wrongful conviction rate.

1. When I refer to Ronald Huff, I refer also to his colleagues Arye Rattner and Edward Sagarin. They published their work first in the October 1986 of Crime and Delinquency as “Guilty Until Proved Innocent: Wrongful Conviction and Public Policy.” Ten years later, they republished their work in book form as Convicted But Innocent: Wrongful Conviction and Public Policy, 1996. The following note appears in the Acknowledgments section of that book: “We have contributed equally to the research and writing in this book, and our names are therefore displayed alphabetically.”

2. At the time their book was published, Ronald Huff was director of the Criminal Justice Research Center at Ohio State University. Rattner was a Professor of Sociology at the University of Haifa, Israel. Edward Sagarin died prior to the original publication the work. He had been a Professor of Sociology at City College and City University of New York.

3. Huff actually asked more law enforcement officials than listed above. The numbers given in the first paragraph include only those who bothered to respond.

4. It would have been better had the last survey choice been “Greater than 5%.” As written, the options excluded estimates greater than 5 percent but less than 6. Perhaps some of those who didn’t’ respond believed the wrongful conviction rate was 5.5% and refused to compromise their ethics by selecting from the options provided. The options also exclude all estimates greater than 10%. Perhaps the rest of those who didn’t respond believed the wrongful conviction rate was 12.5%.

5. The quoted text is from Huff's 1996 book rather than his 1986 article.

1 comment:

William Newmiller said...

Excellent work here! Please continue your series.

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