The Issue

The Research Question

The Study

Approximately 10.6 million people are admitted to our nation’s local jails every year. Although most are released on the day of arraignment or within one week, the average stay is closer over three weeks. It is difficult to imagine how much damage just a few days in jail can do, but research indicates that spending any more than one day in jail can have devastating consequences. This study seeks to address a simple question: What is it about spending any more than one day in pretrial detention (jail) that dramatically alters individuals’ lives for the worse? In The Difference A Day Makes, I draw from in-depth interviews with 258 ethnoracially diverse people accused of low-level, low-risk offenses and 320 hours of observations in Corrections, to show the devastating effects that each additional day in pretrial detention can have on people who are jailed.


The Issue 

Since the 1970s, the United States has relied heavily on its criminal legal system to address societal problems. With a fervor not seen in modern times, behaviors associated with poverty and joblessness, mental health illness, substance abuse disorders, and racial unrest have been criminalized and punitively sanctioned. The state has also turned to the criminal legal system to assist with growing fiscal concerns. The result has been the system’s massive expansion. Budgets and personnel for law enforcement, the courts, and corrections mushroomed to accommodate a 700 percent increase in the incarceration rate and a four-fold increase in those supervised on probation and parole. In 1970, we held in our nation’s jails and prisons roughly 200,000 people. We now hold over 2.2 million. This figure represents one-fifth of the world’s prisoners and makes the U.S. the country with the largest share of its population behind bars. In 1980, probation and parole supervised roughly 1.3 million people. Today, they are responsible for over 4.5 million. All told, today the criminal legal system supervises over five million more people than it did just forty years ago. The carceral net has widened so much that more than one-half of the adults in the U.S. now have an immediate family member who has been to prison or jail. 

The mass incarceration story is in part a story about pretrial detention. Of those incarcerated on any given day in the U.S., approximately 29%, or 750,000, are being held in our nation’s local jails, where roughly 10.6 million people (about half the population of New York State) are admitted every year. Importantly, most of jails’ inhabitants, disproportionately Black and Latino, have not been convicted of the crime(s) for which they are being held. Two-thirds of jail inhabitants are pretrial detainees, defendants awaiting trial or case disposition. The remaining one-third have been convicted and are serving sentences for low-level nonviolent offenses – such as trespassing, vandalism, or shoplifting – that typically require less than one year of incarceration. Because pretrial detainees are often the poorest of the poor, most are held because they cannot make bail. And while the average stay is about 26 days (about 3 and a half weeks), most are released on the day of arraignment or within one week. 

It is difficult to imagine how much damage just a few days in jail can do, but recent research indicates that spending any more than one day in pretrial detention can have devastating consequences, dramatically worsening individuals’ social, psychological, economic, and penal trajectories. This is not just because detention increases the likelihood of conviction on current charges and leads to more severe sentences with conviction, although it does both. Pretrial detention also significantly and substantially erodes individuals’ physical and psychological well-being; reduces employment, wages, and annual earnings; increases the burden of legal financial obligations, often shared with family members, and increases the likelihood of future criminal legal system involvement.


The Research Question 

What is it about spending as little as one day in jail that leads to such devastating consequences? 


The Study 

In The Difference A Day Makes, I draw from in-depth interviews with 258 ethnoracially diverse men and women accused of low-level, low-risk offenses in San Francisco, Chicago, Houston, and Louisville, as well as roughly 320 hours of observations in Louisville’s Metro Corrections, to show how within just the first week of detention, each day the very fact of incapacitation and these harsh conditions of confinement yield 1) accumulated material losses (jobs, housing, cars, debt); 2) lost or weakened connections with conventional ties and strengthened bonds with nonconventional ties; 3) a growing sense of procedural injustices that feed a deep distrust in the legal system and legal authorities; and 4) diminished emotional and psychological well-being. These are losses from which individuals have difficulty recovering. Not surprisingly, where recovery is concerned, individuals whose lives are already characterized by precarity have the greatest difficulty. Just a few days in detention can be devastating for those living close to the margins. Still, even among those of means, as little as one day in jail awaiting case decision can have negative consequences for social, psychological, and economic health and welfare. 

This study has been supported by a generous grant from Arnold Ventures (formerly the Laura and John Arnold Foundation).



Research Team

Sandra Susan SMith

Sandra Susan Smith

Research Lead, Daniel and Florence Guggenheim Professor of Criminal Justice, Carol K. Pforzheimer Professor at the Radcliffe Institute, and Professor of Sociology 

Harvard Kennedy School Research Coordinators

Lindsay Apperson
Katie McMurray

Harvard Kennedy School Research Assistants

Mira Nalbandian
Madeline Phuong
Gabriella Vides-Gold

Radcliffe Research Partners, Harvard University

Haruka Braun
Angela Caloia
Hannah Ezer
Alexia Ingram

University of California, Berkeley, Graduate Research Assistants

Diego Aristizabal  
Carmen Brick 
Isaac Dalke 
Katherine Hood 
Jaqueline Lepe 
Dane Wells 

University of California, Berkeley, Undergraduate Student Research Assistants

Isabel Barbera 
Allison Brooke 
Raven Deverux 
Amarpreet Kaur 
Thea Matthews 
Trinity Morton 
Shalomi Philip 
Alberto Reyna 
Shera Torrey 
Claudia Trost 
Evelyn Villanueva 
Dean Welliver 
Raquel Zitani-Rios 

Research and Commentary

Smith, Sandra Susan. "How Pretrial Incarceration Diminishes Individuals' Employment Prospects.Federal Probation 86.3 (December 2022): 11-18.

Sandra Susan Smith. Pretrial Detention, Pretrial Release & Public Safety. Arnold Ventures Public Safety Series Discussion Paper, July 2022.

Isabella Jorgensen and Sandra Susan Smith, "It’s time for Massachusetts to eliminate cash bail." CommonWealth, April 30, 2022.

Isabella Jorgensen and Sandra Susan Smith, The Current State of Bail Reform in the United States: Results of a Landscape Analysis of Bail Reforms Across All 50 States. HKS Faculty Research Working Paper Series, December 2021.

Sandra Susan Smith and Cathy Hu, “Exploring the Causal Mechanisms Linking Pretrial Detention and Future Criminal Justice Involvement,” pp. 88-109 in The Handbook on Pretrial Justice, DCS Handbook on Corrections & Sentencing, Volume 6 (Pretrial Justice), edited by Jennifer Copp, Stephen DeMuth, and Christine Scott-Hayward, 2021. 

Sandra Susan Smith, Tom Shirley, Damarcus Bell, and Isabella Jorgensen. "Pretrial Detention." Social Policy Data Lab, 2021.

‘I Just Felt So Violated’: Harvard Researcher’s Study Shows ‘Devastating’ Effects of Jailing People Pretrial. National Partnership for Pretrial Justice. 

Sandra Susan Smith, “The Massachusetts Bail Fund is on the right side of the law — and justice.” The Boston Globe, August 18, 2020.