The Mass Shooting Database

I tend not to review many crime maps on Maps Mania. Mainly because I have serious concerns about how accurate they are and the possibility that some crime maps paint a distorted picture of the real levels and locations of crimes.

There are many reasons why a crime map, purportedly showing the locations of recorded crimes in a city, may not be a true reflection of the true crime levels in that city. For example not all crimes are reported to the police. This can be for a variety of reasons, such as victims not feeling comfortable reporting the crime, not believing that the police will actually respond to a report of the crime, or believing that police will be unable to solve the crime. 

Even when crimes are reported, they may not be recorded accurately. For example, on this San Francisco bike theft map a major hot-spot of crime appears to be a local police station (possibly because the address of the police station was used when no theft site could be identified).

These concerns don't really apply to maps of mass killings. This is because mass killings are unlikely to go unreported to the police and their impact tends to ensure that they are largely recorded to the correct crime location. The impact and importance of mass killings also means that the data is likely to be more closely scrutinised and audited. For example the Mass Killing Database, a collaboration between Northeastern University and the Associated Press, tracks all multiple homicides in the United States from 2006 with four or more victims.

Mapping the mass killings in the Mass Killing Database reveals that multiple homicides occur in all kinds of towns and cities in the United States. However, according to USA Today, "Homicides with fewer than four victims are more common in larger cities, but mass killings with higher death tolls often take place in smaller towns or rural settings."

The Gun Violence Archive also collects data on gun-related violence in the USA (the Mass Killing Database isn't limited to mass killings involving only guns). The Gun Violence Archive reports that there have already been 130 mass shootings in the USA so far this year. To date 61 children have been killed by guns in 2023 and 132 children have been injured by guns.

Mother Jones has also been collecting data on mass shootings in the USA since 1982. According to their 'Guide to Mass Shootings' in over three quarters of mass shooting incidents in the USA the guns involved were acquired legally. 

The Mass Killing Database and the Mother Jones Guide to Mass Shootings use different criteria in defining what constitutes a mass killing. The Mass Killing Database isn't limited to gun crimes and Mother Jones only records indiscriminate killings in public places. There are therefore major differences in the number of mass killings between the two different databases. Despite these differences one thing is clear in both databases - the perpetrators of mass killings and mass shootings are overwhelmingly male.