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The FBI’s murder rate mystery

Good luck figuring out what happened with crime in 2021.

Oakland police investigate a fatal shooting at a gas station in October 2021. The FBI crime data for 2021 is based on very little information about crime in California.
Jane Tyska/Digital First Media/East Bay Times via Getty Images

The number of murders rose nationally in 2021, according to new data released by the FBI on Wednesday.

Or maybe it didn’t.

If the FBI’s estimate is accurate, it would mean there were more murders in the US in 2021 than any year since 1994, with the highest murder rate since 1996. But that’s a big “if.” After a change in the FBI’s reporting system, nearly half of law enforcement agencies nationwide didn’t report a full year’s worth of data on crimes in their jurisdiction for 2021.

The estimate was reached without data from New York City, the vast majority of jurisdictions in California — including Los Angeles — and virtually every law enforcement agency in Florida, among others.

This means there are serious limits to what the new data can tell us about what actually happened last year, even as crime becomes a major focus of the Republican push to retake the Senate in this fall’s midterm elections.

The FBI data showed an estimated increase in murder nationally in 2021 of roughly 4 percent, after a nearly 30 percent increase nationwide from 2019 to 2020.

But the FBI switched to a new crime reporting system, the National Incident-Based Reporting System, in 2021, requiring that the country’s nearly 19,000 law enforcement agencies submit data via NIBRS or not submit at all. In theory, the new system should allow for far more granular analysis of crime trends locally, statewide, and nationally: Agencies collect and report substantially more information about each crime incident under NIBRS compared to the prior system.

Unfortunately, only about 65 percent of the US population lives somewhere with an agency that reported any data to the FBI in 2021, and only about 52 percent lives somewhere where law enforcement reported a full 12 months of crime data. Neither the New York Police Department nor the Los Angeles Police Department — two of the nation’s largest police departments — reported data in 2021; the Phoenix Police Department reported only one month of data; and the Chicago Police Department reported just over half a year’s worth of data.

Poor reporting rates means that the FBI had to estimate crime data like never before.

Estimates have always been a part of national crime reporting, but they were usually derived from 5 percent or fewer of agencies that failed to submit full crime data in a given year under the old system, rather than nearly half in 2021. Fewer agencies reporting data than in previous years means the margin of error (or confidence intervals, as the FBI calls it) accompanying each estimate must grow.

The best estimate for 2021 shows around a 4 percent increase in murder nationally, but the increase is within the margin of error, according to the trend study the FBI released. There were an estimated 22,900 murders in the US in 2021, with a lower bound of 21,300 and an upper bound of 24,600 murders. The FBI estimates that there were 22,000 murders in the US in 2020, with lower and upper bounds between 21,000 and 23,000.

Given the bounds of those estimates, murder — like Erwin Schrödinger’s famous cat — could have been up 17 percent or down 7 percent, and there is no way to know for sure which is right.

Violent and property crime showed slight estimated declines, but with even larger confidence intervals. Violent crime was estimated to be down 1 percent with a margin of error between -12 percent and +11 percent, while property crime was estimated down nearly 4 percent with a margin of error between -38 percent and +50 percent — meaning that while the estimate showed a relatively small drop as the most likely outcome, the reality could have been anything between a dramatic drop or an even more dramatic increase.

A 4 percent increase in murder does seem to fit with big city data from 2021, which pointed to an increase of roughly that size compared to 2020.

But early data for 2022 suggests murder is down again in big cities nearly as much as it increased in 2021.

Crime is a big issue in the midterms. But it’s far from clear what’s actually happening.

The FBI release of crime numbers comes at a precarious time. The nation’s crime trend has become a major talking point for many GOP candidates ahead of next month’s midterm elections. Yet many states featuring hotly contested congressional and gubernatorial elections will see no crime estimates published by the FBI this year.

Crime has been an issue in races in Florida, Pennsylvania, and New Mexico, yet the FBI did not release a statewide estimate for any of those states in 2021. Less than 20 percent of Pennsylvania’s population was covered by an agency that reported to the new data system. Only about 7 percent of California’s population was covered in the data, and Florida was the only state in the country without a single non-tribal agency reporting data to the FBI in 2021.

It is not just statewide races where a lack of crime data could be an issue. Runoff elections for sheriff in Los Angeles and Jacksonville, Florida, will take place in November, and fresh crime data could be useful for electorates hoping to evaluate each agency’s performance, but neither agency reported data in 2021.

Accurate crime and policing data is essential for identifying emerging issues and analyzing policy responses at every level of government. Crime data is already impacted by low reporting rates of certain types of crimes (like rape and assault), and the switch to a new system makes it even harder to understand what is happening amid misinformation and inaccuracies regarding crime and policing.

Reporting rates have improved over the last few years as the deadline to make the switch drew closer, though it may be several more years before as many agencies are reporting as used to under the old system. Until then, a large part of gauging crime trends will be estimation — and properly expressing uncertainty about what’s happening will be more important than ever before.

Jeff Asher is a crime analyst based in New Orleans and co-founder of AH Datalytics. Find him on Twitter at @Crimealytics.

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