After the mass shooting of 20 children and 7 adults in Connecticut, I asked: (1) Are such shootings on the rise? and (2) Would a gun control law make a difference in such events?
In a situation like this, it is common to hear that the weapons used were acquired legally (for instance, see Ezra Klein today). This raises the issue of what would happen if the law changed. There is some evidence.
The data came from an extensive tabulation by Mark Follman at Mother Jones. Except for 1999, a year of five shootings (including the Columbine massacre), the assault ban period was peaceful by US standards:
|Years||Shootings||Per year||People shot/year|
*p<0.05 compared with 1995-2004.
Since the expiration of the gun ban in 2004, the number of shootings per year has doubled, and the number of victims per year has nearly tripled. Three of the bloodiest four years shown here occurred since the expiration.
However, the assault-weapon-ban hypothesis does not explain why victims and shootings were not as common before 1994. Has something new happened in the last decade? War? Economic disruption? Lax monitoring of the mentally ill? Whatever the case, renewing the assault weapon ban as a route to pre-2005 conditions seems like a rational response to today’s horrific events.
Update: Using the FBI’s lower threshold for what constitutes a “mass” killing, this analysis by James Alan Fox suggests no change since 2004 in the number of incidents in which four or more people were killed. However, for a view of larger killings (in the US and abroad) see this list, which is consistent with the trend I have described. In other words, these acts are always with us, but advanced weaponry creates an efficiency of scale to allow the possibility of large killings. James Fallows describes the other extreme of what a lunatic can do without any guns at all.