Can Your Birth Year Predict Future Arrest Rates?

Sociologists and criminologists have spent decades studying theories of what impacts crime — whether it’s an individual’s moral character, socioeconomic status, or even the age-old debate of nature versus nurture. 

Now, a group of Harvard University researchers say in an unprecedented longitudinal study that they’ve identified another societal marker that can be used to predict the trajectory of criminal behavior: the changing social and historical context of when someone comes of age based on when they were born. 

The researchers, Harvard sociologist and distinguished professor Robert J. Sampson and Ph.D. candidate Ronald Neil, dubbed this the “birth lottery of history” considering it’s out of an individual’s control regarding the state of policing and criminal justice in America, yet that culture greatly impacts someone’s likelihood of being involved with the system. 

To get to the heart of their data, Sampson and Neil followed arrest rates in the lives of 1,057 Chicagoans as they transitioned out of adolescence to young adulthood over the 23 years from 1995 to 2018, according to the Harvard Gazette. 

Over the two decades, our country saw “significant social change” which shifted more than just the laws within the justice system, but change occurred regarding how adolescents and young-adults come into contact with the criminal justice system. 

Between 1995 to 2018 as the study cohort was coming of age, mass incarceration, aggressive police tactics, changing in police practice and police brutality, and the mid-1990s sudden drop in crime influenced how the adolescents and young adults behaved during the social change.

Looking at their 1,057 longitudinal sample, Sampson and Neil dug deep into the characteristics of the participants — their families, early life neighborhood conditions, and adolescent development.

“We wanted to know not only if there were differences in arrest rates for the different cohorts, but why were there differences,” Neil told the Harvard Gazette. 

“Do these differences reflect fundamental differences in who these people were, or differences in what happened early on in their life? Or did they reflect differences in the larger context through which they were aging?”

Right Age, Right Timing

Sampson and Neil found that it was the latter, considering in many cases, participants with similar moral characters from similar types of families and economic backgrounds had much higher or lower chances of getting arrested depending on the years when they were 17 to 23 years old — the peak ages for arrest.

To further explain this, the researchers detail how the youngest of the cohort was born in the 1990s. Sampson and Neil say this group came of age during a “radically” different time, and in some ways, it was a more peaceful time in the world than other older cohorts would’ve come of age if they were born in the 1980s. 

“Chances of arrest for younger cohorts went down significantly from their peaks in the 1980s,” the Harvard Gazette summarizes. “In fact, the chances of arrest for the older cohorts were nearly double — 96 percent higher — than the youngest cohort, according to the study.”

“The explanation for this can’t just be reduced to the usual suspects — childhood experiences, family structure, demographics, social class, family upbringing — or other individual characteristics,” Sampson echoed.

‘Birth Lottery of History’

Sampson and Neil’s analysis shows just how impactful a few years of societal change can be when it comes to addressing arrest rates that are often blamed on socioeconomic disadvantages and low impulse control.

Approximately 70 percent of children born in the 1980s to disadvantaged families were arrested by their mid-20s, while only about a quarter of disadvantaged children born in the mid-1990s were arrested by that same age, the study found. 

Looking at those same cohorts, the study found that those born in the 1980s with higher self-control had about the same arrest rates as those born in the 1990s with low self-control.

“We should really be looking at not what was wrong or virtuous with individuals of a particular cohort, but rather looking at what’s right or wrong with the larger social environment during the historical period in which they happen to come of age,” Sampson told the Harvard Gazette. “This study is showing that historical changes are built into those very criminal records.”

The results quantify the “power of social change and contribute a new understanding of inter- and intra-cohort inequalities in growing up during the era of mass incarceration and the great American crime decline,” according to the full study.

When speaking with the Harvard Gazette, Sampson further explained the results. 

“Put simply, our results show that when we are matters as much and perhaps more than who we are or even what we have done,” Sampson concludes. 

“To the extent that arrest is a result of substantial social changes in both criminal justice practices and societal norms that strongly differentiate the life experience of successive birth cohorts, independent of individual or family differences, the idea of an individual’s propensity to crime needs reconsideration.”

To further this emerging theory, the researchers say they hope to expand upon their data by looking at inequalities within the cohort, and collect more data through additional interviews and record-gathering.

Ronald Neil is a Ph.D. candidate in Sociology at Harvard University. His current research focuses on explaining patterns of police behavior, understanding the nexus between race/ethnicity and criminal justice systems, and employing a life course perspective to understand offending patterns over time. 

Robert J. Sampson is the Henry Ford II Professor of the Social Sciences at Harvard University, Affiliated Research Professor at the American Bar Foundation, and founding director of the Boston Area Research Initiative.  

The full study can be accessed here. 

Andrea Cipriano is a TCR staff writer.