Behind the scenes: How CBS News analyzed murder resolution rates across the United States

Pandemic since At the beginning of, thehomicide ratein the United States soared at an alarming rate. In almost all major cities, the number of homicides since the start of 2020 is much higher than in the previous year, reversing the decades of homicide decline that began in the early 2000s.  

CBS News investigative teams are how police are dealing with this almost unprecedented murder surge, and why so many are unresolved.The team and the CBS Innovation Lab analyzed data from major cities across the country and found lower homicide clearance rates and large racial disparities among victims. 

What is the "clearance rate"? 

Clearance rates are a tool used by law enforcement agencies and researchers to measure how well police agencies can resolve cases. They are calculated by dividing the number of incidents "cleared" or resolved each year by the number of homicides that occurred in the same year. It doesn't matter if the cleared murder took place in the same year or 10 years ago. Murders are counted in the year they are cleared.  

Why not just use the arrest rate? 

The clearance rate is different from the arrest rate. If a person is arrested, the case will be cleared — this is the most common reason for the case to be cleared — but it can be cleared under other circumstances as well.  

According to the FBI guidelines, you can clear a case in what is called an "exceptional" situation. These so-called "exceptional clearances" run murder liability projects that track cases closed due to the death of a criminal, if the victim refuses to cooperate, or if the criminal tracks unresolved murders nationwide. According to Thomas Hargrove, he refuses to hand over.  

However, FBI data does not distinguish between cases cleared by arrest or exceptional means, and is the only way to obtain consistent data from all law enforcement agencies in the country.  

Why use only 2020. 

The FBI took a long time to release data, and at the time this analysis was done, the latest data release was in 2020.  

Data 

CBS News used two sets of FBI data for this project. A "Return A" file and supplement from the UniformCrimeReporting (UCR) program. Murder report data. Both hold data on murders reported to the FBI by thousands of police agencies across the country.  

The data is published by the FBI in the archaic format first used in the 1960s, so the data manual first published by the FBI needs to be converted to computer code for extraction and conversion. had.  

CBS News analyzed the data and sent the analysis to 14 broadcasters nationwide. Journalists in these local newsrooms used the data to convey their reports, reveal individual stories of unsolved murders, and the family left in search of justice. Meanwhile, the National Investigation Team has done its own investigation to talk about the countries that law enforcement agencies are struggling with. To catch up with the rise in murders — and the community was paying for unresolved murders. 

I want to know more about the CBS News methodology. For those who are interested, we have published the codehere. 

Although the data file used to calculate the clearance rate did not contain racial data, CBS News reported that of different races and ethnicities. I wanted to investigate what the victim's case was like. solved. CBS News answered these questions using the FBI's supplementary murder report data, which contains detailed information about murder victims and criminals. 

However, because the data does not directly indicate whether the case has been cleared, CBS News will use the criminal demographic data to determine if the case has been resolved. Had to use existence. CBS News considered the case cleared if there was demographic data for the offender of a particular incident, otherwise it was considered open.  

This approach has some drawbacks. That is, according to a murder liability project investigation, some agencies submit criminal demographic data to the FBI even if the person has not been arrested and there are no incidents. Witnesses described the criminal, but t was cleared, such as when police did not arrest him. This approach can lead to higher clearance rates than UCR data suggests, but it is the only way to measure clearance by demographics without requesting data from individual institutions in the country.