For those unable or unwilling to read the link, here is some assistance. I have corrected the one math error. Note that a major advantage of the proposition is that prisoners convicted of serious crimes are no longer released early because of a shortage of prison space.

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Following Proposition 47's approval in November 2014, inmate populations in prisons began to fall across California. In Los Angeles, which has the country's largest jail system, the inmate population fell from 18,601 in November to 17,285 in January 2015. According to Jody Sharp, a commander with the Los Angeles County Sheriff's Department, narcotics arrests fell one-third and bookings fell by a quarter in January 2015 relative to the previous year.

A February 2015 report from the state’s Legislative Analyst’s Office claimed that although Gov. Jerry Brown's budget assumed a reduction of 1,900 inmates in 2015-16 due to Proposition 47, this is likely an underestimation of the measure’s effects. The report estimated that state savings would range from $100 million to $200 million beginning in the 2016-17 fiscal year. The governor reduced his proposed annual budget by $73 million and cut the use of private prison beds in half because of earlier-than-expected reductions from Proposition 47.

As a result of jail population reductions from the proposition, Los Angeles County was one of several counties that were able to end "early release," a practice implemented in response to realignment. The Board of State and Community Corrections also credited the measure for a decreased early release trend statewide. In other counties, such as Alameda County and Orange County, sheriffs have closed parts of jails after reductions.[11] Orange County was able to rent out empty jail beds to the federal government for immigration detainees. In San Joaquin County, a reduction in crowding allowed staff to focus more on rehabilitative programs in the county jail.

Garrick Byers, President of the California Public Defenders Association, views Proposition 47 as working. He said, "It reduced the punishment for many crimes from an excessive punishment to a punishment that's more in line with what the crime is. They're still getting a criminal punishment, nobody's getting off free. But it is more commonly probation, more commonly a lower lock-up time, more commonly a punishment that is going to result in rehabilitation."

U.S. Sen. and 2016 presidential candidate Rand Paul (R) praised Proposition 47 in June 2015. He said, "California’s actually done some good things. Proposition 47 about a year ago or six months ago took some of the minor drug felonies and made them misdemeanors and, from my understanding, you have more room in your prisons now for violent criminals. They’re not getting out early."

Others view Proposition 47 as being short-sighted. Los Angeles City Councilman and former LAPD chief Bernard Parks noted that while drug-related arrests fell, thefts and residential burglaries rose. He stated, "But what they failed to consider is that people who are using drugs are also committing other crimes. How do they stay heroin users? How do they support their habit? … People don't want to understand that I can't be a crack addict and have a profession. Nobody's giving me drugs. I rob and burglarize and steal."

KCRA looked into whether inmates released under Proposition 47 ended up back in custody. The news site noted the following on March 16, 2015:

In Placer County, 28 inmates have been released since November 2014 and four ended up back in custody. Thus, 14 percent of those released ended up back in custody.

In Stanislaus County, 127 inmates have been released and 12 ended up back in custody. That is a nine percent return rate.

In Sacramento County, 42 inmates have been released and 25 are back in custody. In other words, 60 percent ended up back in custody.

The California Department of Corrections and Rehabilitation has released 3,068 inmates since November and 14 have ended up back in the system. That is a return rate of 0.5 percent.

As of mid-August 2015, 4,347 prisoners were released from state prisons under Proposition 47.

In early December 2015, Los Angeles County officials voted to establish two task forces that would help residents affected by Proposition 47. One task force would strategize how to reach out to convicted residents who could change their charges. The other task force would consider how to connect ex-offenders with job training programs. Los Angeles County Public Defender Ron Brown said his office has facilitated about 16,700 petitions that successfully reduced individuals' charges under the measure since it passed in 2014.


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Another interesting quote:

In October 2013, the incarceration rate of the United States of America was the highest in the world, at 716 per 100,000 of the national population. While the United States represents about 4.4 percent of the world's population, it houses around 22 percent of the world's prisoners.

And another:

As of December 31, 2010, the International Centre for Prison Studies (ICPS) at King's College London estimated 2,266,832 prisoners from a total population of 310.64 million as of this date (730 per 100,000 in 2010).