Appear before the judge on your birthday

Using all French court decisions from 2002–2014 with 6 million decisions, we estimate significant impact on sentence lengths, but mainly for those defendants present at trial—equivalent to 3.5 days reduction. The average sentence length is 95 days. Focusing on the three-month threshold (the median sentence length), defendants are 1.6% less likely to be sentenced above this threshold on their birthday. Including controls for gender, crime, age, and nationality, the effect is 1.1% and remains statistically significant at the 5% level. Disaggregating the components of the sentence length reveals the impact is greatest on probation sentences–defined as the prison sentence people get in case of violation of their probation. Notably, individuals with drug offenses—but not violent offenses—benefit from this judicial leniency. They are 5% less likely to have sentences above three-months if sentenced on their birthday and appearing at trial.

For the United States, the birthday effect shows up only for the “days” component of the sentence, not for the “months” component.

That is all from a paper by Daniel L. Chen and Arnaud Philippe, via Robert Dur.


What is the effect if the crime was committed on your birthday?

Also, it helps if you get sentenced early in the morning or just after lunch:

"The graph is dramatic. It shows that the odds that prisoners will be successfully paroled start off fairly high at around 65% and quickly plummet to nothing over a few hours (although, see footnote). After the judges have returned from their breaks, the odds abruptly climb back up to 65%, before resuming their downward slide. A prisoner’s fate could hinge upon the point in the day when their case is heard."

What if you get sentenced on your birthday just after lunch?

There is no reason to take the lunch study serious:

(See also the comments to the study published in PNAS.)

Interesting food for thought. Thanks.

Someone should do a study on the effect of the anonymous delivery of a box of four dozen Krispy Kreme doughnuts on the morning of day of sentencing. This easy to control -- matched pairs of the same types of cases, same race and gender of defendants and victims, same judge, same day of week. Do you send them to the court clerk or do judges have their own clerks?

Also, at least at the federal level, most judges have already worked-up the sentencings the day, or even days, before the hearing. Sometimes there are kinks to work out (e.g., disagreements about the offender's appropriate criminal history); but the judge still has a pretty solid idea of where the defendant will end-up in light of those contingencies.

If you pretend that the people were sentenced on the day before their birthday, rather than their actual birthday, is their any effect? Is the effect really about measurement error on age?

A better question -- what about the victim's birthday?

Now I know that Ty likes to pretend all crimes are victimless. (To him, the justice system is just a bunch of non-white guys dragged before others, to be judged, for absolutely no discernable reason. All that matters is making sure they face minimal consequences.)

But let's pretend that crimes have victims. Does the victim's birthday factor into the sentencing?

I'm sure Ty will spend all day thinking about this.

The effect sizes are _very_ small. In the cases where there are effects, my guess would be that people expecting a more strict sentence are more likely to be absent on their birthday.

This being the 500th anniversary of the Reformation, which affirmed Paul's rational belief that salvation is all about the self, we should acknowledge that economists, who worship the rational belief in the self, are God's messengers. Those who believe in good works as the key to salvation are not only misinformed but are leading others astray.

Don’t be so coy... if you feel Thaler isn’t deserving of the Nobel, just come out and say it.

This sums up nearly all psychology research for the last forty years. Statistically significant, yes, even amusing. Of any real consequence? No.

You are being far too kind to psychology research. Statistically significant? Only in the sense that if you take any set of data, select the right bits, apply every test you can think of, one of them is bound to turn up a result someone will publish and hence help you get tenure.

Any real consequence? If only such transparent bullsh!t had no real world consequences! Take implicit bias tests which are the issue du jour at the moment. No evidence that implicit bias exists. Caused massive changes to pretty much everything everyone does. The rule seems to be the more obviously bullsh!t a psychology result is - and look at "safe spaces", triggering, recovered memories and so on - the greater impact it will have on public policy. There is no evidence that people can be triggered by saying "rape". But every workplace and college in America has been forced to change.

I thank you for the post in favor of mandatory minimum sentencing.

I know, I know... as if we needed more evidence. But thank you anyway.

"remains statistically significant at the 5% level"

In other words, not at all significant in the everyday sense of the term "significant".

For this sort of data mining, you need vastly higher levels of significance to be meaningful.

This strikes me as a small effect/data snooping/garden of forking paths type of problem. The effect is small and probably random given the universe of other possible effects (which we would not all test because they don’t suggest an obvious meaning). Calling Andrew Gelman...

I'm having trouble seeing how a three-month prison sentence is optimal for anything. How can a crime be serious enough to warrant prison, yet so minor that the perpetrator can be safely released only three months later? And yet this is the average?

Three months is time enough to ensure completion of a drug treatment program, along with various "life skills" programs. And while the latter might seem absurdly remedial —on par with this: — it very often is necessary and eye-opening. Separating criminals from their usual habitat and associates, while teaching them the basics of hygiene and punctuality for three months, can be effective.

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