This is a pretty good article explaining the change in clearance rates for murders. In the early 1980s, police cleared about 70% of all homicides; now it is only about 50%.

Excerpts from the Article:

For homicide detectives, 2020 brought good news and bad news. On the one hand, police across the nation solved more murders — in absolute numbers — than in any year since 1997, according to data reported to the FBI. On the other hand, because new homicides increased sharply, the reported rate at which killings were solved, known as the “clearance rate,” declined to a little below 50%.The lower clearance rate in 2020 was an extension of a long, steady drop since the early 1980s, when police cleared about 70% of all homicides, and a decline that experts say was exacerbated by the pandemic. (The FBI won’t release 2021 numbers until later this year.)In most cases, clearing a crime means at least one suspect was arrested and charged with the crime. However, individual agencies have different ways of calculating clearance, with some clearing a case once police identify a suspect, and others if an arrest is made. At the national level, the FBI uses blunt math to calculate a clearance rate, dividing the number of crimes that were cleared — no matter which year the crime occurred — by the number of new crimes in the calendar year. By clearing old and new cases, a department’s rate in any given year could exceed 100%. This leaves the numbers prone to statistical “noise,” but they can be useful for examining trends over the long term.

National Homicide Clearance Rate Dropped to Historic Low

From 2019 to 2020, police across the country solved 1,200 more murders, a 14% increase. But murders rose twice as quickly — by 30%. As a result, the homicide clearance rate — the percentage of crimes cleared — dropped to a historic low. About 1 of every 2 murders was solved.

New murders
1980
1990
2000
2010
2020
0
5,000
10,000
15,000
20,000
25,000
20,250
Cleared murders
1980
1990
2000
2010
2020
0
5,000
10,000
15,000
20,000
25,000
10,115
Murder Clearance Rate
1980
1990
2000
2010
2020
0%
20%
40%
60%
80%
100%
50%
Source: Uniform Crime Reporting (UCR) Program data, processed by Jacob Kaplan of Princeton University.
Clearance has long been the primary metric that law enforcement agencies use to assess their effectiveness at solving crime. Low or declining clearance rates often lead to increased political pressure on police leadership, and calls for more hiring or funding. For police to “clear” a crime, they usually need to identify and arrest the suspect. But according to more granular data collected by the FBI but reported by fewer agencies, at least 400 murders cleared in 2020 were solved by “exceptional means.” That means police believed they had enough evidence, but were unable to make an arrest. This occurs when the suspect has died, can’t be extradited or if prosecutors refuse to press charges. Critics say police use clearance by exceptional means — sometimes colloquially described as putting “bodies on bodies” — to artificially inflate clearance numbers.
National Clearance Rate, by Crime Type

Across the country, murders and manslaughters are cleared at the highest rates, at 50% and 69% respectively. Other crimes, especially property crimes without physical injuries, were solved at much lower rates.

Violent Crime Clearance Rate
Murder
1980
2000
2020
0%
20%
40%
60%
80%
100%
50%
Manslaughter
1980
2000
2020
0%
20%
40%
60%
80%
100%
69%
Rape
1980
2000
2020
0%
20%
40%
60%
80%
100%
30%
Assault
1980
2000
2020
0%
20%
40%
60%
80%
100%
47%
Robbery
1980
2000
2020
0%
20%
40%
60%
80%
100%
27%
Property Crime Clearance Rate
Burglary
1980
2000
2020
0%
20%
40%
60%
80%
100%
14%
Moter Vehicle Theft
1980
2000
2020
0%
20%
40%
60%
80%
100%
12%
Theft
1980
2000
2020
0%
20%
40%
60%
80%
100%
15%
Arson
1980
2000
2020
0%
20%
40%
60%
80%
100%
21%
Source: Uniform Crime Reporting (UCR) Program data, processed by Jacob Kaplan of Princeton University.
Why are police only solving 1 in 2 murders? Many scholars and police department officials say murders are becoming more difficult to investigate, while some victims’ families say police spend too much energy on things other than solving crimes. Philip Cook, a public policy researcher at the University of Chicago Urban Labs, has been studying clearance rates since the 1970s. He cautioned that fewer clearances than in the 1960s and ‘70s may not necessarily be a bad thing. “It also could be that the standards for making an arrest have gone up and some of the tricks they were using in 1965 are no longer available,” Cook said of law enforcement. Every story about a person convicted of murder on shoddy evidence and later exonerated was once counted as a “successful” homicide clearance. Cook, and other experts, mostly pin the long, steady decline in clearance rates onto the kinds of homicides police are being asked to solve. Data from the Bureau of Justice Statistics shows that over time, a growing proportion of killings are being committed by strangers and unknown assailants, as opposed to people the victim knew. The data also shows that unknown assailants are increasingly using firearms rather than knives, fists or other close-quarter weapons. As the social and physical distance between killers and victims increases, detectives say they have fewer leads to follow. But the changes in the nature of homicides — which some criminologists call case mix — are not destiny. Some cities routinely solve two or three times more homicides than others, even after accounting for case mix. Within departments, some detectives solve many more homicides than others. “That variation tells us something important,” said Charles Wellford, emeritus professor in the Department of Criminology and Criminal Justice at the University of Maryland-College Park. “It says that it’s not inevitable that there will be low clearance rates.”

Meanwhile, in communities where trust in law enforcement is low — often communities of color — homicide detectives have a hard time getting witnesses to talk to them, said Peter Moskos, a professor at the John Jay College of Criminal Justice. “If people criticize the police constantly, it is natural that people would be less willing to talk to police,” Moskos said. Without useful leads, police solve fewer murders, and the perception that they are ineffective leaves witnesses and victims skeptical that talking to the police will do any good. In other words, Moskos said, it’s a vicious cycle. There are many reasons people avoid speaking to the police, from the lack of confidence Moskos raised, to a fear of violent reprisals. According to Melina Abdullah, co-director for the national community organizing group Black Lives Matter Grassroots, another important reason is that police often criminalize crime victims — specifically in Black communities — treating them as suspects rather than survivors. A police and prison abolitionist, Abdullah said that clearance rates are not useful measures for addressing violence in communities. “Clearance rates, especially when we talk about acts of community violence, might give some kind of temporary sense of relief. But it’s not justice,” Abdullah said. “I don’t know anybody who’s felt like, ‘OK, now I can rest because this murder has been cleared by the police.’ ”Clearances don’t necessarily lead to criminal penalties like incarceration. In the nation’s 70 largest counties, nearly one-third of people accused of murder were acquitted or had their charges dismissed, according to a 2009 report from the Bureau of Justice Statistics. That’s the most recent year with local prosecution and conviction data available on the national level. Shari O’Loughlin, chief executive officer at The Compassionate Friends, a national organization of support groups for families that have lost a child, says that an arrest or conviction “closes the information gap.” “For most parents, siblings and grandparents who experience the loss, it’s critical for them to know what had happened,” O’Loughlin said. “But it’s not as if [an arrest] makes the loss, or the pain, better because nothing makes up for the loss of a child.” And not knowing who killed their loved ones often means the family continues living in fear, said Jessica Pizzano, the director of victim services at Survivors of Homicide, Inc., a nonprofit organization that provides service to families of homicide victims in Connecticut. “Is the murderer in my neighborhood? Will I run into them at the grocery store? Or when I’m pumping gas?” Pizzano said. “These are real fears that families live through.”Pizzano said families want accountability. “They just want that person to never, ever do that to another family again,” Pizzano said.
Homicide Clearance Rate, by Law Enforcement Agency

Look up the homicide clearance rate that hundreds of police departments reported to the FBI in 2020, the most recent data available, and how much it changed from the three-year average from 2017 to 2019.

FILTER
All States

All States
SORT BY
New murders

New Murders
Search an agency
AGENCY
NEW MURDERS
CLEARED MURDERS
CLEARANCE RATE
Minneapolis Police Department
Minnesota
79
+99%
+39 cases
30
+50%
+10 cases
38%
-25%
-12 pct. point
Fresno Police Department
California
77
+88%
+36 cases
26
-21%
-7 cases
34%
-58%
-47 pct. point
Prince George’s County Police Department
Maryland
72
+40%
+21 cases
42
+20%
+7 cases
58%
-14%
-10 pct. point
Tulsa Police Department
Oklahoma
72
+17%
+10 cases
61
+41%
+18 cases
85%
+21%
+14 pct. point
Orange County Sheriff’s Office
Florida
69
+70%
+28 cases
45
+53%
+16 cases
65%
-10%
-7 pct. point
Shreveport Police Department
Louisiana
69
+52%
+24 cases
20
-5%
-1 cases
29%
-37%
-17 pct. point

This list excludes agencies with fewer than five homicides because small numbers cause the rate to fluctuate in ways that may not be meaningful and are dependent on the facts of specific cases. Some of the nation’s largest police departments, including the Chicago Police Department, did not report clearance data to the FBI and are also excluded. Criminologists and the FBI caution not to directly compare different departments’ clearance rates because agencies may report and define their numbers differently. Data that law enforcement agencies report to the FBI may differ from what they cite elsewhere.

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