While the US imposes an age of majority on youthful offenders at the age of 18, many other nations rely on higher ages such as 20 or 21 to demarcate the separation of juvenile offenders and juvenile correctional systems from their adult counterparts.
In recent years, many have argued that the US should move to a higher age of majority, such as 21. Such changes, generally known as “raise-the-age” reforms, are currently under consideration by several state legislatures, such as Connecticut and Illinois. Moreover, many states have already passed legislation raising the age of majority from 16 or 17, to the age of 18.
Advocates for these changes argue that corrections systems need to account for the lack of emotional, psychological, and intellectual maturity in youthful offenders. In particular, they argue that youthful offenders may not be mature enough to properly understand the costs of the harsher punishments that characterize adult correctional systems, and therefore to understand the consequences of their criminal acts.
If these youthful offenders are undeterred by adult punishments, then imposing harsh sanctions on youthful offenders will likely be ineffective at reducing crime and create additional costs for taxpayers and offenders, with no public safety benefit. As a result, the argument runs, raise-the-age laws represent relatively costless ways of reducing correctional costs and improving outcomes for youthful offenders.
A recent research paper co-authored by the two of us finds that this narrative of costless improvement is very likely incorrect. We find that youth are in fact deterred by the harsher punishments imposed at the age of majority.
In particular, we find that youth sharply reduce their offending at precisely the age of 18, when the imposition of harsher punishments presents real and palpable consequences. To reach our conclusions we analyzed high-frequency data that records all criminal offending in California for both juveniles and adults from 1998 to 2006. We constructed daily crime counts where crimes are organized by the precise age of offenders in days. We then used rigorous statistical techniques known as regression discontinuity designs to analyze the patterns of offending by youth immediately before their 18th birthday, and the patterns of offending by youth immediately after their 18th birthday.
Our principal finding is that youth criminality experiences a large, sharp, and discrete drop at precisely the age of 18 as a result of greater sanctions.
A key component of the analysis is that youthful offenders are essentially identical on either side of their 18th birthday; so unlike studies that rely on correlations between age, punishments and offending, our method likely reveals a causal channel between the punishments youth face and the level of criminal offending they engage in.
This stems from fact that youth are inherently the same in all respects at the age of 17 years and 364 days as they are at the age of 18 years and one day—with the only meaningful difference being that they are thrust into the harsher sanction regime of the adult justice and corrections system. Faced with this age-imposed change in how they are treated by the justice system, young people rationally choose to reduce their level of offending.
We also find that the prevalence of violent crimes such as murder, rape, robbery and assault by youthful offenders is more likely to change than other crimes. These violent crimes decline by up to 12 percent as a result of the greater sanctions imposed at the age of majority.
Our findings suggest that there is a slightly lower—up to eight percent—reduction in property crimes. Moreover, not all youth are equally deterred by the greater sanctions. While effects are present for both male and female offenders, the data suggest that female offenders respond more forcefully. Moreover, there are racial differences in the pattern of deterrence suggesting that perhaps not all youth face an equal jump in sanctions at age 18.
The result is hardly surprising from a theoretical standpoint. Researchers have long argued that offenders are deterred by harsher punishments. But our conclusions represent meaningful new findings in that deterrence has now been demonstrated for youthful offenders with the use of high-quality data. While it may still be the case that youth are less able to rationally process the threat of harsher punishments than mature adults, our paper casts substantial doubt on the oft-repeated claim that youth are categorically incapable of internalizing the costs of sanctions and reducing their prevalence of criminal acts.
Our findings imply that young people who have passed the age of majority at 18 are deterred from carrying out many crimes by being exposed to harsher adult sanctions. Reducing sanctions for those between the ages of 18 and 21 would likely lead to an increase in criminal offending.
Hence, raise-the-age policies extending the age of adult jurisdiction beyond 18 are far from the “costless improvements” that some have claimed, and would likely lead to greater rates of crime including violent crimes.
We refrained from considering past changes in the age of majority from 16 or 17, to 18. Our data only enables us to analyze the patterns of offending in California where the age of majority has been 18 for all the years in which high-quality data is available.
While we conclude that harsher sanctions imposed at age 18 have value in deterring crime, a truly comprehensive evaluation of raise-the-age policies would need to quantify costs and benefits in terms of public expenditures, as well as costs to offenders and victims. Such estimates have yet to be generated. As a result, further increases in the age of majority should be considered with great care.
Nicholas Lovett, Ph.D. is a researcher with the Department of Economics at the University of Wisconsin-Whitewater. He can be reached at: https://sites.google.com/site/nicholasblovett/home. Yuhan Xue, Ph.D. is a researcher with the Department of Economics at the University of Wisconsin-Whitewater. She can be reached at: https://sites.google.com/site/xueyuhan/. They welcome readers’ comments.