Skip Navigation

California: Increased Incarceration Had Limited Effect on Reducing Crime for Over Two Decades

On Heels of Proposition 47, Report’s Findings Support Further Reforms to Reduce California’s Prison Population – and Proves This Can Be Achieved Without Added Crime.

February 12, 2015

Since 1990, increased incarceration had a limited impact on reducing crime nationwide, concludes a new report from the Brennan Center for Justice at NYU School of Law. In What Caused the Crime Decline?, a team of economic and criminal justice researchers examine over 40 years of data, gathered from 50 states and the 50 largest cities. Among the report’s new findings:

The report offers a close look at California, where the prison population has exploded since the mid-1970s, partly driven by sentencing policies like the 1990s “three strikes you’re out” law. With a prison population that increased by 514 percent from 1980 to 2006, California could not build prisons quickly enough to accommodate the growth. In 2009, the state’s prisons were at nearly double their capacity. In 2011, the U.S. Supreme Court found that California prisoners’ health and safety were unconstitutionally compromised. It ordered the state to reduce its prison population to 137.5 percent of capacity (approximately 38,000 to 46,000 prisoners) within two years. As of 2013, Californian imprisons 355 people per 100,000, compared to 496 for the U.S. California spent $8.618 billion on state corrections in 2013.

The Center will host a briefing call today at 1 p.m. ET to discuss the report’s findings. Dial In information: 1–800–514–0831; Confirmation Number: 38955210

Nationwide and California-specific findings are summarized below:

  • Crime: Crime across the United States has steadily declined over the last two decades. Between 1980 and 2013, crime in California dropped by 61 percent. And the national crime rate was cut in half.
  • Incarceration: Increased incarceration has been declining in its effectiveness as a crime control tactic for more than 30 years. It had some effect, likely in the range of 0 to 10 percent, on reducing crime in the 1990s. Since 2000, however, increased incarceration had a negligible effect on crime. In California, as the state’s prison population increased by 514 percent between 1980 and 2006, the effectiveness of incarceration in reducing crime declined to essentially zero. A number of states, including California, Michigan, New Jersey, New York, and Texas, have successfully reduced their prison populations while crime continues to fall.
  • Other Factors: Increased numbers of police officers, some data-driven policing techniques, changes in income, decreased alcohol consumption, and an aging population played a role in the crime decline. In particular, the report finds CompStat is associated with a 5 to 15 percent decrease in crime. In California, CompStat was introduced in San Diego in 1999, Sacramento in 1998 or 1999, Los Angeles in 2002, Fresno in 2006, Oakland in 2009, and San Francisco in 2009. The report also includes new information on the effects of unemployment, the death penalty, and other theories on crime.

“Some have argued that despite the immense social and fiscal costs of America’s mass incarceration system, it has succeeded at reducing crime,” said report co-author Oliver Roeder. “But the data tells a different story: if reducing crime is the end goal of our criminal justice system, increased incarceration is a poor investment.”

 “This report amplifies what many on the left and right have come to realize in recent years: mass incarceration isn’t working,” said Inimai Chettiar, director of the Brennan Center’s Justice Program. “A better use of resources would be improving economic opportunities, supporting 21st century policing practices, and expanding treatment and rehabilitation programs, all of which have proven records of reducing crime, without incarceration’s high costs.”

“This groundbreaking empirical analysis from the Brennan Center shows that, on examination, the easy answers do not explain incarceration’s effect on crime,” wrote Joseph Stiglitz, a Nobel laureate in economics and University Professor at Columbia University, in the Foreword. “This report presents a rigorous and sophisticated empirical analysis performed on the most recent, comprehensive dataset to date.”

“In California, over-incarceration has become such a dire problem that the U.S. Supreme Court found that California prisoners’ health and safety were unconstitutionally compromised,” said Lauren-Brooke Eisen, co-author of the report. “While California has taken some steps to comply with the Court’s order to reduce its prison population, this report’s findings support further reforms to reduce California’s prison population – and prove this can be achieved without added crime.”

Click here to read the full report, What Caused the Crime Decline?

Read about the crime decline in Illinois, Florida, Louisiana, Maryland, New Jersey, New York, Ohio, Pennsylvania, Texas, and Virginia.

Click here to read more about the Brennan Center’s work to improve the criminal justice system.

For more information or to speak with an expert, contact Naren Daniel at (646) 292–8381 or