Do Uncommon Names Turn Kids Into Criminals?


The answer to that question is almost certainly “no,” but a new study that is getting lots of media attention does claim that there is a correlation between having an uncommon name and being more likely to show up in the juvenile justice system. The study finds this relationship to be true both for blacks and whites.

As the authors clearly state in the abstract of their paper, “Uncommon names are likely not the cause of crime but correlated with factors that increase the tendency toward juvenile delinquency.”

To me, that makes the result a lot less interesting. It is kind of like saying that we know that people who regularly wear orange jumpsuits are more likely to be criminals, when orange jumpsuits just happen to be the required uniform in the state prison. The wearing of orange jumpsuits isn’t the cause of the criminal activity, but it is highly correlated with past criminal involvement.

And to be honest, I think there is a good chance that even the claimed correlation between unusual names and criminality is wrong. I only quickly glanced through the academic paper, but it seems to me like the authors have made a mistake that will bias their results.

The authors first compute criminality for each name by taking the ratio of the number of juvenile delinquents with that name and dividing it by the number of children total with that name. The higher that ratio, the more criminal the name. But then the authors take the log of that ratio. The problem is that the log of zero is equal to negative infinity, so any name for which that ratio is equal to zero gets dropped from the analysis.

The kinds of names that will have a ratio of zero are uncommon names for which no one with that name is a juvenile delinquent.

If I understand correctly what they are doing, if exactly one person has a particular name, the only way that the observation for that name will be included in their sample is if that person is a juvenile delinquent! This leads to a powerful bias toward mistakenly concluding that people with uncommon names are more likely to be criminals.


Gee I hope not...
I might be in trouble otherwise...


If the authors did indeed make the mistake that Levitt accuses them of having made, I agree that the result will probably be inaccurate.

However, if uncommon names were indeed correlated iwth higher criminality, this would be a far more interesting observation than the one about orange jumpsuits and crime. The difference is that in Levitt's example, crime causes orange jumpsuits. No one is seriously suggesting that committing a crime causes you to go get a funny name. This would be a more interesting clue to follow up: if committing criminal acts isn't causing you to have an uncommon name, why are the two variables correlated? I agree that it's not as exciting to know things correlated with crime as it is to know things that cause crime, but you have to take what you can get.

Josh Penslar

Good catch! If I taught Stats 100 this would definitely be an extra-credit question on my exams. If nothing else, it would pick out the Freakonomics readers in the class!


Clever observation, Steven!

This could be exacerbated further, since they did NOT change the names of people with unusual spellings for common names (Patric is one example they gave). A birth certificate misspelling could result in a one-of-a-kind name and make the study more vulnerable to the effect you describe.

This could have been made manifestly apparent if they listed the ratio of delinquents to total people with the name of Michael, vs. the ratio of delinquents to total people with unique names.


@ Francis
Seeing as parents choose the name, one could assume that it's their influence which is the correlation: if you are a parent who is more likely to bestow an unusual name, then...


Yesterday, I saw a report about this which disturbed me. It suggested that this study's results could be used by police to catch criminals. I don't know about everyone else, but that sounds a bit too much like Minority Report to me, and a serious misapplication of this study even if it is sound.

Paula Hall

It's been a while since I read Freakonomics, but didn't the authors find that uneducated and/or single parents were more likely to give their children uncommon names? If that is the case, then that this study found a correlation would not be surprising.


In reality, though, how many TRULY unique names (that is, only 1 person in the entire country) are there? My suspicion is that it is incredibly small, and does not/would not have very much of an effect when compared to the total number of 'unique' names (as defined by the study).

But it is still something worth considering.

Leland Witter

With a name like Leland, would I be more likely to be a white-collar criminal?

Eric M. Jones

There is the tale of Wayne as a middle name predisposing one to commit heinous acts:

The FREAKest Links:
“4real Wayne Smith” Edition
Not Wayne again…

But I have to agree that it is the parents who should bear the blame. A kid named "Prince Vlad Dracula". is going to have problems in tthe schoolyard....


The effect would still be felt for any 0 for 2's out there, or 0 for 3's, and so on. As the likelihood of an "0 for" goes down, you'd see a decreasing impact from this, but the more "unique" the name, the more likely this is to be a factor.


I think his point is not that people with truly unique names may be disproportionately left out if they are crime-free. It's the fact that names with 0 criminals will be universally dropped from the analysis. So 1-of's will be dropped unless they're criminals, but so will folks who share their name with just one other person, and neither of them are criminals.

Nice catch Levitt, if that is indeed a mistake the author made.



It isn't just that the names have to be truly unique, but the problem Levitt describes will manifest whenever an uncommon name has no juvinile delinquents with that name the ratio is zero and the log is negative infinity. So you could have an uncommon name like Elana, and even if there are several or many of you with the same name, but no delinquents named Elana you end up with a negative infinity log.


Using the exact same methodology, I could prove people people with uncommon names are more likely to become professional athletes, e.g. BenJarvus Green-Ellis, Tayshun Prince.


The name doesn't have to be "truly" unique, only rare enough (say, no more than a few hundred) that the group has no one incarcerated, which is a pretty rare occurrence (roughly a percent of the total population, I believe). On the surface, it seems like a pretty egregious oversight.

caveat bettor

Let's keep a closer eye on Nassim Taleb.


I'm a bankruptcy lawyer-- my sample set consists of the names on my files. My colleagues and I have long seen a link (I won't call it a correlation) between strange names (first or last) and bankruptcy filings. It's just one more handicap.


If criminals only knew how difficult it is to track down John Smith or Mike Jones, they'd give their kid these names. It would give them a leg up in the family business.

On a more serious note, if there is any co-relation, I suspect that it is because minorities are over represented in the system and minorities seem to lean towards uncommon names.

Hasn't it been said that these names put them at a disadvantage in job hunting. Allows them to be screened out before the screener is aware of their race. The perfect cover for racism.


OK - keeping this discussion in mind we had a pediatric patient who's mother thought a beautiful name for the baby girl was Clamydia... Wonder if this is a self fulfilling prophecy of this girl's future. Would be another interesting study. - or didn;t you already talk about something similar?


You might very well be right and their correlation wouldn't hold up for review, but if true the results are somewhat interesting.

My interpretation would go like this: what their are really measuring is something like social conformity of upbringing. A parent that is more likely to give an uncommon name is more likely to resist social norms, and pass that behavior on to their child. Resisting social norms probably leads to people that are more likely to try socially unacceptable behavior such as drugs and crime. Because you have a larger percentage that dabble in these social taboos, you'll also have a higher percentage who end up getting caught.