To What Degree Do the Criminal Justice and Child Welfare Populations in California Overlap?


It has been reported that “70 percent of all California state prison inmates have spent time in the foster care system.” Sounds compelling, right? This statistic has been repeated in a congressional hearing and associated report.1; cited in at least one book2, news article3, nonprofit fundraising letter4, and literature review5; and touted on the webpages of at least four national organizations supporting foster youth.6-9

After much investigation, however, we have failed to find its source. And without a source and associated methodology upon which to judge its veracity, we can only conclude that it is unfounded.

Long story short: There is no evidence to support this claim.


Not surprisingly, there is data documenting an overlap of criminal justice and child welfare populations in California. Although the degree of that cross-system overlap varies based on the population of individuals studied and the definition of child welfare “involvement” used, none approaches 70%.

  • A 2011 study conducted by the California Department of Corrections and Rehabilitation (CDCR) and the California Senate Office of Research surveyed incarcerated individuals in California’s prisons. Roughly 14% of respondents reported having been in foster care at some point in their lives.10

  • In an analysis developed by the Child Welfare Data Analysis Bureau at the California Department of Social Services (CDSS), in partnership with CDCR, linked administrative data were used to document the prevalence of child welfare involvement among inmates. Findings indicated that 28% of inmates incarcerated between 2000 and 2013 had a history of either an open child welfare case for in-home services or an out-of-home foster care placement.11

Most recently, we collaborated with CDSS’s Child Welfare Data Analysis Bureau and the California Department of Justice to examine this question. We extracted the records of every youth and young adult younger than age 25 who was arrested and booked in California in 2014 and 2015 and then linked those records to historical child welfare records dating back to 1998. This retrospective examination revealed that 43% of young adults arrested had a history of reported maltreatment. Although high, 43% is nowhere near 70% and reflects the broadest possible definition of child welfare involvement (including all allegations, regardless of whether they were investigated or substantiated). Findings indicated that 18% of our population had history of substantiated maltreatment victimization, whereas 9% had experienced placement in child welfare supervised out-of-home foster care.12

The CDN: Data Darwinists

Statistics are important. They can spur policy change, inform the design of programs and delivery of services, and facilitate collaboration to everyone’s benefit. But if numbers are wrong or pulled out of thin air, they have the potential to obfuscate the best solutions, negate impact, and stymie improvement to the detriment of all.

Stray statistics have the potential to do more harm than good. And they will persist until soundly refuted by better data, elegant research design, and lots of hard work. Here at the CDN, we will continue questioning and replicating to replace stray statistics with valid research findings that will inform, invigorate, and improve policies for all.

We are data Darwinists. We believe in survival of the fittest … data.

Actively engaged in the matter,

1 U.S. House of Representatives’ Committee on Ways and Means, First Session of the 110th Subcommittee Hearing on Income Security and Family Support. (2007, July 12). Children who “age out” of the foster care system (p. 106). Retrieved from

2 Kenny, J., & Kenny, L. (2010). Striking back in anger: Delinquency and crime in foster children. Retrieved from

3 SFGate. (2009). ‘Aged-out’ foster youth at terrible risk. Retrieved from

4 South Los Angeles Homeless Transition Age Youth and Foster Care Collaborative. (2013). Organization description and background. Retrieved from

5 Harbert, A., & Dudley, D. (2007). Emancipating foster youth: Literature review. San Diego, CA: San Diego State University School of Social Work, Academy for Professional Excellence. Retrieved from

6 Inspire Life Skills Training. (2016). The problem. Retrieved from

7 HP Serve. (2016). The need. Retrieved from

8 A Sense of Home. (2016). Why it matters. Retrieved from

9 AboutOne. Please help the over 600,000 children in foster care. Retrieved from

10 McCarthy, S., & Gladstone, M. (2011). State survey of California prisoners: What percentage of the state’s polled prison inmates were once foster care children? Policy Matters. Sacramento, CA: California Senate Office of Research. Retrieved from

11 California Department of Social Services, Research Services Branch. (2014). California state prison-child welfare data linkage study. Retrieved from

12 Children’s Data Network. A Descriptive Analysis of the Maltreatment Histories of Youth and Young Adults Arrested in California. Retrieved from

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