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New Research Provides In-Depth Look at Sentence Enhancements in California

Berkeley, CA, March 23, 2023 — A new report released today by the nonpartisan California Policy Lab (CPL) provides a comprehensive analysis on the role of sentence enhancements in California’s criminal legal system. Sentence enhancements are typically applied at the discretion of both prosecutors and judges, and the application of an enhancement lengthens a person’s sentence by adding additional years to it. For example, a person convicted of a second-degree robbery could receive three years for the robbery, but have an additional 10 years added to their sentence if they received an enhancement for using a gun during the robbery. CPL conducted this study through a research partnership with the Committee on Revision of the Penal Code, a state agency that studies and makes recommendations to improve California’s criminal legal system.

There are more than 100 unique sentence enhancements in California though the researchers found eight enhancements account for about 80% of the sentence years that have been added since 2015. Because enhancements increase an individual’s prison sentence, that in turn increases the size of the state’s prison population at a given time as people are incarcerated for longer periods of time.

“Since the 1980s, California has added numerous enhancements to the penal code that have lengthened sentences and increased the state’s prison population. More recent reforms have dialed back the use of enhancements, though they are still applied frequently and affect the sentences of the majority of currently incarcerated individuals,” explains co-author Steve Raphael, a public policy professor at UC Berkeley.

Key Findings

Prevalence: Roughly 40% of individual prison admissions since 2015 have sentences lengthened by a sentence enhancement. Among the currently incarcerated, the prevalence of enhanced sentences is much higher, impacting the sentences of approximately 70% of people incarcerated as of 2022.
Sentence length: Sentence enhancements increase the average sentence by roughly 1.9 years (or 48%) for all admissions. The impact is larger for people receiving longer sentences.
Four enhancement types account for 80% of sentence years added since 2015, including: the state’s Three- Strikes law, firearm enhancements, the nickel prior (which adds five years for a prior serious offense), and gang enhancements.
Racial, ethnic, and sex disparities: Sentence enhancements are more likely to be applied to men. Black people and American Indian individuals are the most likely to receive enhanced sentences, followed by Hispanic people, White people, and Asian or Pacific Islander people.
Potential drivers of disparities: Most, but not all, of the inter-racial and inter-sex disparities in the use of enhancements can be explained by group-based differences in case characteristics observable in CDCR data, including the number of prior prison commitments, the number of conviction charges, the most serious conviction offense, and the county of sentencing.
County variation: Enhancements are applied unevenly across California counties, with the lowest application rates in Bay Area counties and Southern California coastal counties, and the highest rates among far Northern counties, the counties in the Central Valley, and Inland Empire counties.

Additional background
This analysis uses administrative records from the California Department of Corrections and Rehabilitation (CDCR). The report does not address enhancements for jail sentences, however jail enhancements are usually very short and likely used infrequently.

The California Policy Lab translates research insights into government impact. Through hands-on partnerships with government agencies, CPL performs rigorous research across issue silos and builds the data infrastructure necessary to improve programs and policies that millions of Californians rely on every day.

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