THINK AGAIN
Think of two different judges passing sentence on a couple of first-time offenders, both up for cashing forged cheques for less than $100. In the first case, Judge A sentences the accused to 30 days in jail. In the second, Judge B gives the other guy 15 years.
You could say that each judge displayed his bias, one towards leniency, the other towards severity. What you couldn’t say is that the joint effect of the two judgments amounted to a reasonable average. Leaving aside whether seven and a half years would be fair, the point is that neither criminal experienced that fairness.
A US judge named Marvin Frankel came across that very scenario, as well as many other shocking disparities, when he wrote a report on sentencing policy back in 1973. His findings were so revelatory that it resulted in the US adopting sentencing guidelines in an attempt to iron out such extremes.
In their new book, Noise: A flaw in human judgment, Daniel Kahneman, Olivier Sibony and Cass Sunstein cite Frankel as an early pioneer in the battle to rid institutions and systems of “unwanted variability”. Or, to give it the more vernacular term the authors employ and which is the book’s title: noise.
They ask us to imagine an archery target at which a number of people take aim. If all the arrows land to one side of the bullseye, the accuracy problem is one of bias. But if the arrows land scattered all around the target, it’s one of noise. The same applies for all large systems, institutions and professions, from the law to medicine to the insurance business.
In 2012, an FBI-commissioned study asked 72 fingerprint experts to look again at 25 pairs of fingerprints they had evaluated only seven months earlier. Roughly one in 10 was changed.
