Once again there have been media reports of mass killings by gun shots in USA. Actually, they are more or less a daily occurrence now, it is just the reports that are sporadic. Here is a report that shows the number of mass shooting events each day for 2015 so far:
Actually there is a web site with a further two years data but it needs to be collated into the same form of daily totals before analysis can be done.
Are there cycles in mass shootings? What could cause variations in their occurrence? These questions were examined. This is a spectrum of cycles present in the above 9 months of data. Cycles periods in red are significant except the 365 day one.
We may take the two most prominent cycles of 6.99 and 3.494 days as being a week and half a week. This is not surprising as people’s habits vary greatly by the day of the week. Further analysis shows that there is little difference between the five week days, but compared to them Saturday has 100% more mass shootings and Sunday has 140% more. It reminds me of the old saying “the devil finds work for idle hands”.
As there is only 9 months data, we cannot say that there is a 365 day cycle but it seems quite likely, as seasonal weather patterns play out. There are more killings in the summer months. The other three cycles of 17.35, 5.96 and 2.64 days do not seems to be related to any commonly know cycles.
Combining the above cycles to see how they fit the original data also allows a possible projection. Ideally a longer base period would be used for this, but we can look and see whether or not the future follows the past patterns.
The original data and explanations are available here as well as further data going back several years.