Sentencing Enhancements

Assessing the impact of sentencing enhancements on incarceration in California.

Sentencing enhancements are laws that increase the total incarceration term for a crime based on aspects of how the crime was committed or who committed it. The Three Strikes law quickly became the most notorious enhancement law since its adoption in California in the 1990s. This highly punitive sentencing scheme resulted in infamous cases such as that of Leandro Andrade, who received two life sentences after shoplifting movies.

While Three Strikes may be the most well-known enhancement law, there are dozens of such statutes in the California penal code. However, little research has been done on how they affect sentencing and incarceration, even as many suspected that sentencing enhancements contributed considerably to the overcrowding crisis in the California penal system. SCPL conducted the first quantitative analysis of sentencing enhancements laws in California, in partnership with the San Francisco District Attorney.

We found that enhancements account for a significant proportion of time served in jail or prison—over one in four years served from felony sentences in San Francisco. Our results show that while enhancements are sentenced in a relatively small proportion of felony cases, they more than double the sentence imposed for the base crime in these cases.

We presented our results to the Sentencing Commission at the San Francisco District Attorney’s office. Citing this research, San Francisco D.A. Chesa Boudin eliminated the use of Three Strikes and other enhancements in his office.


Elan Dagenais

Data Scientist

Sharad Goel


Joe Nudell

Lead Engineer