Saturday, June 30, 2012

Crime declines too big to attribute to police falsifying stats

Whenever it's mentioned on this blog that crime rates have declined for the past two decades, a slew of anonymous commenters show up who claim that crime is just as high as ever but police are intentionally underreporting their data, or else victims have been scared away by a phantom "stop snitching campaign." Grits certainly doesn't deny that occurs - in fact instances have been well documented in places like New York City and Dallas. (The HBO drama The Wire famously portrayed this phenomenon as a recurring theme at the Baltimore PD.) But some data - like murders - are difficult to fudge. And surveys of crime victims - which are frequently compared to reported crime data to estimate the extent of underreported crime - consistently show crime drops as substantial as the reported numbers.

So I was interested to see via CrimProf blog this New York Times piece titled, "Crime report manipulation common among New York police, study finds" (June 28), which reported that "An anonymous survey of nearly 2,000 retired officers found that the manipulation of crime reports — downgrading crimes to lesser offenses and discouraging victims from filing complaints to make crime statistics look better — has long been part of the culture of the New York Police Department." One survey respondent put it this way: “Assault becomes harassment, robbery becomes grand larceny, grand larceny becomes petit larceny, burglary becomes criminal trespass.”
NYPD responded by attacking the study's credibility: “The latest report from Eterno and Silverman appears designed to bolster the authors’ repeated but unsupported claims. ... The document provides no explanation of how the survey sample was constructed.” NYPD says the survey contains a sampling bias because those surveyed are self-selected. The surveyors didn't attempt to construct a valid sample group, the way pollsters conduct surveys of voters, for example, but instead calculated data from respondents who self-selected and may represent the views of an outspoken, disgruntled subset. Basically NYPD is saying the survey is invalid for the same reason one can't compare internet polls to those conducted by pollsters using statistically valid sampling techniques.

New York City has reported an 80% drop in major crimes, according to the Times,  so if the decrease is really due to fraud by officers downgrading charges, that's a massive conspiracy, and IMO an unlikely one. I don't doubt that virtually every large department succumbs to pressure to fudge crime statistics to some extent, but that would only affect the numbers at the margins. The massive crime reductions recently witnessed IMO can't be explained by manipulating crime stats. The Times story concluded giving voice to a view much closer to Grits' own:
research conducted by Franklin E. Zimring, a criminologist at Berkeley Law School, that compared the department’s crime data for homicide, robbery, auto theft and burglary to insurance claims, health statistics and victim surveys and found a near-exact correlation.
In an interview Wednesday, Mr. Zimring said his research found that the 80 percent decrease in those four crimes reported by the department from 1990 to 2009 was “real.”

He said that there was always “some underreporting, and there is some downgrading in every police force that I know of,” but that his research showed that any manipulation was too minuscule to significantly affect the department’s crime statistics.
There are a number of powerful political constituencies who consider falling crime rates more of a problem than good news: Police unions, elected DAs and career prosecutors, prison systems and their employees - all of them see job security in rising crime rates and risk to their budgets in acknowledging crime has fallen. None of them want to admit such a motive, which is why on this blog such claims are only ever made by anonymous trolls unwilling to attach their names to their opinions and unable to support them with anything but supposition and anecdote. Even if police downgrade thefts on police reports, for example, the number of insurance claims filed wouldn't show a corresponding drop unless there were actually fewer thefts. And while police surely have incentives to downplay crime, respondents to crime victimization surveys (which do use statistically valid sampling techniques) have no reason to falsely downplay crime.

That said, all crime data is imprecise because of both victim over- and under-reporting as well as differences in reporting methodology, accuracy and completeness among departments. So it's easy (and frustratingly common) to misinterpret short-term trends and unwise to draw conclusions without several years of data for comparison. Grits often thinks many folks' expectations of reported crime data are simply too high: They can tell us broad trends but will never capture every jot and tittle of crime that occurs. Taken together with other sources, though, they paint a convincing picture of unprecedented and IMO undeniable long-term crime reductions over the past 20 years.


Anonymous said...

Funny how the reduction in crime seems to correspond so well with the increase in incarceration rates over the last 20 years.

jdgalt said...

The preceding comment illustrates the real problem here. We need to learn WHY the crime rates have fallen, so that cities, states, and police departments with nasty policies (ranging from NYPD's unjust practice of stopping-and-frisking to the use of unjustified SWAT raids to terrorize the public) are not given the credit if they're not really responsible.

Above all, we need to support state and local candidates who will fire those police who insist on being at war with their employers.

Anonymous said...

I listened again to the news last night as the list of all the new taxes that will be put in place secondary to Obamacare between now and 2018. So, goes your money, so, goes your ability to make choices for yourself, and so, goes your FREEDOM.

As the list was read you can see something else in it. The taxes on companies and citizens will push everyone into a single payer health care system some time after 2018.

I was just now watching a talking heads panel on the news. In general the topic was fraud and waste in government programs. Five people were on the panel. Four people where in agreement on what to me is fact. There is a great deal of fraud and waste in government run programs. One panelist maintained that there was virtually no fraud and waste in any government program. That fraud and waste for the most part existed in companies in the public sector only. It wasn’t said out loud but, the point was clear –what is needed is more government control and that control probably means Federal control Scary stuff and what’s even scarier is this attitude seems to be on the rise.

Who knew Socialism could be put in place as fast as it has been in the United States the last 3 years.

Just what do you suppose the prison system and the health care for that prison system is going to look like under Socialism down the road? Whatever it looks like the citizens of the State of Texas aren’t going to have much to say about it.

I hope crime is down. The public in the Freeworld are going to loose their more of their rights. What’s in store for the prison population? My advice is don’t get locked up.

Gritsforbreakfast said...

JDG and 11:33, the best estimates say that increased incarceration accounted for about a quarter to a third of witnessed crime reduction, with the remainder attributable to other causes. Grits recently discussed various theories proposed to explain the non-incarceration reasons here.

Keep in mind, Texas now releases more people from prison ever year (more than 70,000) than the entire prison system housed in 1990. The theory that increased incarceration caused all the crime reduction always relies on the pretence (as at 11:33) that incapacitation is the sole cause of reduced crime, but offenders don't stay in prison forever. More prisons are part of it, but most crime reduction is attributable to reasons unrelated to incarceration and probably to societal trends unrelated to the justice system.

11:55, prisons are by definition "socialist" enterprises. There's not a market for them. They exist (even "privatized" ones) as an expression of raw government power. I always find it ironic when those who think the government can't find its ass with both hands and a flashlight express blind faith in police, prosecutors and the prison system. There's a disconnect there I've never heard the ideologues adequately explain.

Anonymous said...

I've heard (sorry, nothing to cite) that crime rate follows the economy. I'm wondering if that's a major cause here.

Anonymous said...

Incapacitation definitely reduces crime--at least for those criminals who are actually locked up. But what if it does more? Even though parole rates are going up, it's commonly understood by criminologists that lots of criminals "age out" the older they get. So maybe just locking lots of criminals up until they mature beyond their prime law breaking years also contributes to the reduction in overall crime. Or maybe it's even more basic than that. I know Grits will never admit this, but maybe for lots of criminals prison really does work. They go there, learn their lesson, decide they never want to go back, and become law abiding citizens when they are released. What a novel concept. Punishment for bad behavior really works!

Gritsforbreakfast said...

"I know Grits will never admit this ..."

Uh, except for two comments above where Grits wrote that "the best estimates say that increased incarceration accounted for about a quarter to a third of witnessed crime reduction."

You're arguing against a strawman/caricature that exists only in your own head, not opinions I've expressed here.

The Fishing Physicist said...

The above link goes to what I believe is the true basis for the increases in the crime rate of the 60s, and 70s, and the decreases in the 80s and later.

The Fishing Physicist said...


Age and Crime - Effects Of Age Structure On Crime Rates

Anonymous said...

Grits, you are right when you said,
"prisons are by definition "socialist" enterprises. There's not a market for them. They exist (even "privatized" ones) as an expression of raw government power." but, if America can't reverse it's trend toward European Socialism; as the barker at the circus said, "Folks you ain't nothing yet!"


Anonymous said...

And everyone said that tough on crime doesn't work!

Maybe prosecutors and the law enforcement know what they are talking about after all.

Or better yet, maybe the storie of 120 degree weather in prison is starting to hit the streets and abiding by the law is a much better alternative.

Nah, couldn't be that

Gritsforbreakfast said...

"Nah, couldn't be that"

Well, about a quarter to a third of it could. It doesn't explain the rest, though.

Anonymous said...

Must be that rumor about a federal mandate that all criminals will have to purchase a legal retainer plan on their

M Johnson said...

Within the field of criminology, changes in crime rates based on arrest data (typically from the UCR) over time are verified as generally valid by triangulating the different forms of data. In addition to using victimization data, data from self-report surveys of crime are compared with official data. Self-reports are based on asking individuals about their own involvement in criminal behavior, and are widely considered the most valid assessments of actual involvement in crime/delinquency, and the ONLY source of data equipped to address causes of criminal behavior. Combining all crime from arrest data (UCR) and national victimization surveys (NCVS) still leaves out a large chunk of unrecorded crime (by definition, victimless crimes are excluded from victimization surveys and arrest data is limited to index crimes). If all three sources of data are showing similar trajectories, it is safe to assume that the changes are true in a broad sense.

DWI Houston Lawyer said...

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Anonymous said...

The lower crime rate in NY does not come without a cost; stop rates are disproportionate.

Course this could explain why NY homicide rate has declined 17% this year while Chicago's has increased 38%.

If the NYPD stop and frisk procedure has reduced crime, which do you want?

Anonymous said...

Today's news.........

Soon as this stops, crimes going back up in NY.