I spent much of my work time over the past six months running around South Los Angeles, for a Zocalo series on the region.

To my surprise, I heard quite a bit from people in South L.A. about a new budget formula in California. It relates to the savings of Prop 47.

Awareness of the details of Prop 47 runs high in South L.A., because of its potential to change the lives of people who have criminal convictions. Among other things, Prop 47 reduces incarceration, which generates budget savings for the state. The formula about which there was so much discussion involves how the state’s Department of Finance – which works for governor – determines what those savings are. The amount of savings is then directed to services that include re-entry programs, various prevention programs to keep people out of jail, and services for crime victims.

Such programs are seen as vital to continuing progress in South L.A. What people in South L.A. knew – but what is poorly understood elsewhere – is that Prop 47 didn’t establish a calculation or formula. It left it up to the governor. As the California Budget & Policy Center put it in a recent analysis, “when it comes to calculating state savings from Prop. 47, the Governor not only has the last word, he has the only word.”

And Brown has used that power in unsurprising ways: by being cheap. His department’s calculations were well below other estimates – and the promises he made to voters on behalf of Prop 47, which he supported.

The annual savings were supposed to be in the hundreds of millions of dollars. Brown’s estimate for 2015-16 was $40 million. The governor’s team achieved this with what the LAO and CBPC have shown is an unrealistic assumption.

That assumption was about what would have happened in voters had rejected Prop 47. The governor’s team assumes the state would have housed inmates in state prisons at relatively low cost. But it’s much more likely that, with the state prisons already full, the additional numbers of people in prison would have been housed in much more expensive spaces provided by contractors. The difference is nearly $20,000 per prisoner.

As CBPC concluded,

“By assuming that Prop. 47 has primarily reduced the need for state prison beds, rather than for “contract beds,” the Governor’s formula understates the savings that were actually achieved during 2015-16 by more than $100 million.”

This may seem obscure to you, but in South L.A., many people knew these details. To the point that Brown was facing criticism in small neighborhood papers. And to the point that the governor’s would-be successors should expect to be asked if they will change the way Prop 47 savings are calculated.