Key Trends in the Uncertain Metrics of Terrorism (Anthony H. Cordesman, CSIS)

It is now some 15 years since 9/11, the United States has not only conducted a constant campaign against terrorism since that time, but has been at war with violent Islamist extremists in Afghanistan, then Iraq, and then Syria. It has gone from counterterrorism to a mix of counterterrorism and counterinsurgency in these three states where no meaningful boundaries exist between them while it increasingly is a partner in counterterrorism with nations in Europe, Africa, and Asia and throughout much of the Islamic world.

http://csis.org/publication/key-trends-metrics-terrorism