Tuesday's school shooting in Kentucky is one of at least 1,592 mass shootings since 26 people - children and adults - lost their lives at Sandy Hook Elementary School in 2012. At least 1,801 people have been killed and 6,404 wounded.
The counts come from the Gun Violence Archive, a database that tracks events since 2013 in which four or more people (not counting the shooter) were shot at the same general time and location. The database’s researchers comb through hundreds of news stories, police reports, and other sources each day and individually verify the reports.
Still, since some shootings aren't reported, the database is likely missing some shootings, and some are missing details. The count is also a constant work in progress, so some of the numbers and details may be slightly imprecise.
Depending on whose definition of 'mass shooting' is used, the numbers look different (the Gun Violence Archive counts all shootings in which four or more people were shot but not necessarily killed, excluding the shooter), but one indisputable fact is that the United States has more gun-related violence than any of its peers in the developed world.
According to United Nations data compiled by Simon Rogers while at the Guardian, the US had 29.7 firearm homicides per 1 million people in 2012, while Switzerland had 7.7, Canada had 5.1, and Germany had 1.9.
Americans frequently debate why the problem exists and if or how it should be addressed, but a major factor involves the sheer number of weapons in the U.S. and how easily they can be obtained:
Criminal justice experts widely recognize that America’s unusually high levels of gun violence are a result of cultural and policy decisions that have made firearms far more available in America than in most of the world. For the US, that means not just more mass shootings, but more gun violence in general.