This project created a database that enables the assessment of the features and trends in all deadly mass shootings in America between 1980 and 2018.
In these data, mass shootings encompass all incidents with four or more gunshot fatalities, not including the shooter, within 24 hours. Existing publicly available databases on deadly mass shootings of 10 focus only on those that occur in public spaces but were part of another criminal event. The effort of the current database to be more inclusive enables the examination of not only the characteristics of deadly mass shootings that occur in public, but to also examine all the other mass shootings that occurred over this period, including those that happened in private spaces among family members. In all, the database developed contains information on 720 incidents that occurred in both public and private spaces between 1980 and 2018, although they occurred at a somewhat higher consistency in more recent decades. Among the key findings of the analysis of the current database are the 1) absence of stark increases or decreases in the frequency of deadly mass shooting incidences between 1980-2018, although they occurred at a somewhat higher consistency in more recent decades; 2) the occurrence of most deadly mass shootings was in private residences, with a large portion being family-related; 3) public mass shootings were rarer than family-related and felony-related shootings; 4) the weapon most often used was handgun; and 5) in over half of all incidents, at least one child was killed, yet only 2.5 percent of these incidents occurred in school and 90.9 percent occurred at home.