Penal Code section 1233.1
(a)
The per capita cost to the state to incarcerate in a state prison and supervise on parole an offender who fails local supervision and is sent to prison.(1)
The per capita cost in this subdivision shall be calculated as the sum of both of the following:(A)
The marginal cost to incarcerate an offender in prison multiplied by the average length of stay in prison.(B)
The marginal cost to supervise an offender on parole multiplied by the average length of stay on parole multiplied by the percentage of offenders admitted to prison who are subsequently released to parole supervision.(2)
The marginal cost to incarcerate an offender in prison specified in paragraph (1) shall be calculated by dividing the portion of the budget of the Department of Corrections and Rehabilitation that is annually adjusted based on changes in the prison population, including, but not limited to, pharmaceutical costs, by the average daily prison population.(3)
The marginal cost to supervise an offender on parole specified in paragraph (1) shall be calculated by dividing the portion of the budget of the Department of Corrections and Rehabilitation that is annually adjusted based on changes in the parole population by the average daily parole population.(4)
In carrying out the calculations pursuant to this subdivision, the Department of Finance, in consultation with the Department of Corrections and Rehabilitation, shall use data from the most recently completed fiscal year.(b)
The probation failure rate, calculated as the total number of adult felony probationers, individuals on mandatory supervision, and individuals on postrelease community supervision, sent to state prison as a percentage of the average adult felony probation, mandatory supervision, and postrelease community supervision population for that year.(c)
A felony probation baseline admission to prison rate for each county, calculated as an average of the annual felony probation admission to prison rate for calendar years 2022 and 2023.(d)
A mandatory supervision baseline admission to prison rate for each county, calculated as an average of the annual mandatory supervision admission to prison rate for calendar years 2022 and 2023.(e)
A postrelease community supervision baseline admission to prison rate for each county, calculated as an average of the annual postrelease community supervision admission to prison rate for calendar years 2022 and 2023.(f)
The probation failure rate for each county shall be calculated as the total number of adult felony probationers, individuals on mandatory supervision, and individuals on postrelease community supervision, sent to state prison from that county, as a percentage of the county’s average adult felony probation, mandatory supervision, and postrelease community supervision population for that year.(g)
An estimate of the number of adult felony probationers each county successfully prevented from being incarcerated in state prison. For each county, this estimate shall be calculated as the actual number of individuals from felony probation admitted to state prison from each county in the previous calendar year subtracted from each county’s felony probation baseline admission to prison rate, calculated pursuant to subdivision (c), multiplied by the average daily population of felony probation for each county in the previous calendar year.(h)
In calculating probation failure to prison rates for the state and individual counties, the number of adult felony probationers sent to state prison shall include those adult felony probationers sent to state prison for a revocation of probation, as well as adult felony probationers sent to state prison for a conviction of a new felony offense. The calculation shall also include adult felony probationers who are sent to state prison for a conviction of a new crime and who simultaneously have their probation terms terminated.(i)
A mandatory supervision failure to prison rate for each county. Each county’s mandatory supervision failure to prison rate shall be calculated as the number of offenders supervised under mandatory supervision pursuant to subparagraph (B) of paragraph (5) of subdivision (h) of Section 1170 sent to prison from that county in the previous calendar year as a percentage of the county’s average mandatory supervision population for that year.(j)
An estimate of the number of felons on mandatory supervision each county successfully prevented from being incarcerated in state prison. For each county, this estimate shall be calculated as the actual number of individuals from mandatory supervision admitted to state prison from each county in the previous calendar year subtracted from each county’s mandatory supervision baseline admission to prison rate, calculated pursuant to subdivision (d), multiplied by the average daily population of mandatory supervision for each county in the previous calendar year.(k)
A postrelease community supervision failure to prison rate for each county. Each county’s postrelease community supervision failure to prison rate shall be calculated as the number of offenders supervised under postrelease community supervision pursuant to Title 2.05 (commencing with Section 3450) of Part 3 sent to prison from that county in the previous calendar year as a percentage of the county’s average postrelease community supervision population for that year.(l)
An estimate of the number of felons on postrelease community supervision each county successfully prevented from being incarcerated in state prison. For each county, this estimate shall be calculated as the actual number of individuals from postrelease community supervision admitted to state prison from each county in the previous calendar year subtracted from each county’s postrelease community supervision baseline admission to prison rate, calculated pursuant to subdivision (e), multiplied by the average daily population of postrelease community supervision for each county from the previous calendar year.(m)
The county return to prison rate. The combined individual county return to prison rate shall be calculated as the total number of offenders supervised by a county probation department as felony probationers, or subject to mandatory supervision pursuant to subdivision (h) of Section 1170, or subject to postrelease community supervision, who were sent to prison, as a percentage of the average adult felony probation, mandatory supervision, and postrelease community supervision population for that county.(n)
A baseline return to prison rate for each county, calculated as an average of the county return to prison rate defined in subdivision (m) for calendar years 2022 and 2023.(o)
It is the intent of the Legislature to modify the calendar years upon which the baseline admission to prison rates specified in subdivisions (c), (d), (e), and (n) are based on, as necessary, to minimize the extent to which factors unrelated to performance affect county performance incentive payments calculated pursuant to Section 1233.3.
Source:
Section 1233.1, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=PEN§ionNum=1233.1. (updated Sep. 17, 2025; accessed Oct. 20, 2025).
