For several years now, I have been tracking the crime rates reported in the FBI's Preliminary Semiannual Uniform Crime Report. The 2016 post, with notes on the data, is here. The 2018 post is here. For an earlier look at regions, rather than states, see this post from 2014.
For the current report -- data for the first half of 2018 versus the first half of 2017 in cities over 100,000 population -- we once again see that California compares unfavorably with the rest of the country. This year, though, the year-to-year change is only worse in violent crimes, not property crimes.
For property crimes, there was no significant difference between
the California cities in the sample and those in the rest of the
country, a 5.1% drop for the former, and a 4.9% drop in the latter. This
confirms that the trend I noted with full-year, state-total data in this post
last year, that there was a shift in the relative rates after
Realignment and Proposition 47, but since then California has tracked
the trend of the rest of the country, though at its new, higher level.
For violent crimes, the California cities in the sample had essentially no change, a drop of 0.6%, while the comparable cities in the rest of the country enjoyed a continuing decline of 4.9%.
Once again, the proponents of releasing more criminals can half-truthfully say that their so-called "reforms" have not been followed by an increase in crime, but the whole truth is that California is missing out on the drop seen by the rest of the country.
It is true, of course, that California is not the only state softening its incarceration policies, but it has gone further than other states in this regard. According to "reform" advocate John Pfaff, the national drop in prisoners has been "pretty small" and two-thirds of it has been in California. (Locked In, p. 111.) Thus if more severe cuts cause increased crime, we would expect to see California do worse than the rest of the country, and that is indeed what we see.
Why has California's higher relative property crime rate plateaued while the violent crime rate continues to separate further from the national rate? It could be a one-year glitch. We must be careful not to make too much of a single year's numbers. However, it could be that Realignment and Proposition 47 cause their damage primarily in property crimes, that damage is done, and the permanent shift is now complete, while Proposition 57 causes more damage in violent crime area. Prop. 57 was dishonestly sold to the people as a measure for "nonviolent offenders," but it includes people with violent records whose present offense of conviction is "nonviolent." It necessarily applied more to harder-core criminals, because the low-hanging fruit had already been picked by the earlier measures.
So here are some more numbers that tend to confirm what common sense would lead us to expect. I don't claim them as hard proof, but the burden of proof is on those who assert counter-intuitive propositions like "We can improve public safety by releasing more criminals sooner." Common sense isn't always right, but it usually is, and contradicting it requires compelling proof. I'm not seeing it.
I have the general impression that property crimes are not prosecuted with rigor in California, which would tend to, especially over time, depress reporting. Is this accounted for in the FBI statistics?
I have always paid more attention to homicide statistics, because people do tend to reliably report dead bodies.
I think your general impression is likely accurate. I am a prosecutor and I live in the jurisdiction in which I work.
For some empirical data, I have been a victim of several property crimes in the last 5 years (residential burglary x2, auto burglary, and identity theft x2). Oddly, despite living in the same place for 15 years, none before that. I reported have some, but not others. My reporting decisions were motivated by the necessity of a police report for insurance purposes as well as likelihood of any law enforcement investigation (beyond taking the report, which is now done online with no police officer involvement for many crimes). My guess is that once people see that law enforcement doesn’t really do much about many of these cases, they stop calling. I did and will continue to do so.
No, the FBI numbers do not account for nonreporting. They are only crimes known to the police. That is a shortcoming of the data.
On a national level, we have the National Crime Victimization Survey as a cross-check for this problem. Because the NCVS is a survey, it does not suffer from this shortcoming, though it has others. See this post.
NCVS does not yet publish state-by-state data, though we were told a while back that was coming.
So it is quite possible that California has been doing even worse relative to the rest of the country with regard to property crimes than the FBI numbers indicate.