Analysis of Mass Shootings and Gun Ownership in the United States
Overview
It should come to no one's shock that there is a gun violence crisis in the United States right now. As of July, there had been 372 mass shooting in 2022 and the US had not gone a single week without a mass shooting.
My analysis project focused on two research questions:
1. Is there a relationship between gun ownership and gun violence in the United States?
2. What parts of the United States have been most afflicted with mass shootings?
To begin this analysis, I began my work with two datasets. First, historical data of mass shootings from 1920 to 2022 with a full breakdown of casualties, year, and description. The second data set looked at registered firearms by State in 2019 and 2021.
Analysis
Mass Shootings
Before we begin - we should define what is a mass shooting. These are incidents of public firearm violence, in which the shooter claims at least four victims. As we can see from the graph below, there has been a 41,975% increase in mass shootings over the last 100 years.

There has been a steady increase in casualties from 1920 to 2000 in the United States. From 2000 to present we see a sharp increase, with casualties rising by 1,051% from 2000 to 2010. Since 2010, we have seen a 60% increase in gun violence in the U.S.
Overall, individuals were 100 times more likely to be injured versus killed in a mass shooting. On average, there are four people injured for every person killed.

The data showed that the cities with the highest number of mass shooting casualties are Chicago, Paradise (NV), and Philadelphia. While the States with the highest number of casualties are California, Illinois, and Texas.

Gun Ownership
It is staggering to see the number of registered firearms. In 2019, there was a total of 5,201,947; that number increased to 7,511,303 in 2021.
An important thing to remember when seeing these numbers is that these reflect legal and registered firearms. There are only six states which require the registeration of firearms under law. Thus, the majority of guns fly under the radar and remain unregistered. There is an estimated 393 million total firearms in the United States.

Overall, southern states have more federal registered firearms compared to the Northeast. Only two states showed a decrease in registered firearms from 2019 to 2021: Connecticut (-9.13%) and Illinois (-1.18%). The three states with the highest increase are South Dakota (206%), North Dakota (133.3%), and Mississippi (127.3%).
Conclusions

Overall, there appears to be a relationship between number of firearms and risk of gun violence by state.
The states with a higher number of registered firearms generally have a higher number of gun violence casualties.

The Federal Assault Weapons Ban lasted from 1994 to 2004.
After its expiration in 2004, we can see a dramatic increase into present day. Mass shootings were 70% less likely to occur during the ban compared to present day. Some of the deadliest mass shootings in US history have occurred in our lifetime.
Future Work
- Accessing earlier records for firearm ownership
- Additional data on shooter demographics (age, gender, race, income, etc.)
- Further breakdown mass shooting incidents, looking at political party of state leadership
References
https://www.kaggle.com/datasets/rprkh15/history-of-mass-shootings-in-the-usa
https://www.thoughtco.com/gun-owners-percentage-of-state-populations-3325153
https://www.cbsnews.com/pictures/gun-ownership-rates-by-state/
https://en.wikipedia.org/wiki/Federal_Assault_Weapons_Ban