After the event in Arizona is seems people are making claims that the number of multiple victim shootings has been on the rise. Well that’s not really true:
While Thomas didn’t refer to trends over a longer period than just three years, the numbers for the longer term are murky as well. To more easily analyze Fox’s data — which goes back to 1976 — we averaged the number of incidents for each five-year period (or, in the case of 2006 to 2009, a four-year period). Here are the results:
• 1976-1980: 20.6 incidents annually
• 1981-1985: 16.8
• 1986-1990: 18.2
• 1991-1995: 23.0
• 1996-2000: 20.0
• 2001-2005: 21.0
• 2006-2009: 25.5
More to the point it seems the number of incidents has been rather inconsistent. Of course somebody will point out that the period involving the lift of the “assault weapon” also followed by an increase in these incidents I’ll point out that the period involving the implementation and enforcement of the “assault weapon” ban was followed by an increase in these incidents as well and thus we can pretty much factor out that piece of legislation as having any effect on the number of these incidents.
The article is a good read.
Their choice to average every five years concerns me a little… There could be outliers in either direction that is being lost in that averaging function, and you are not left with an overall trend. Simply doing up a graph and throwing on a trendline (*cough*) would be a lot more illustrative on the way spree shootings are leaning…