Terrorism Data Remains a Mess

I’ve recently been trying to get a handle on terrorism trends in Pakistan, and in that process have been reminded of the problems in terrorism datasets. Based on extant data, I could tell you two stories about Pakistan: terrorism in Pakistan is either getting progressively worse or has gotten considerably better since 2009.

Here is the basic trend for terrorism in Pakistan using the National Consortium for the Study of Terrorism and Responses to Terrorism (START) Global Terrorism Database (GTD).


Compare that with the trend for all terrorism using the National Counterterrorism Center’s World Incident Tracking System. (Through some process opaque to me, the U.S. government decided to stop producing this data series. Or they likely continue to produce it, but just don’t provide it to the outside world. And ignore the redline, which is just the mean across the years shown.)


If you believe GTD, you should be really worried about Pakistan. If you believe NCTC, we may have turned a corner. Get your “Mission Accomplished” banner ready.

The evidence is a little more consistent when looking at just suicide terrorism. Here is the data from the University of Chicago’s Project on Security and Terrorism (CPOST). Sadly, this data hasn’t been updated since October 2011, suggesting they ran out of funding, and also meaning the 2011 data below is incomplete. But, the data suggest a strong peak at 2009, and then sizeable decreases since then, even with the incomplete 2011 data.


Finally, compare that with the GTD data for just suicide attacks. Strong peak in 2007, and then a more modest decline since then.


I don’t have much in the way of conclusions, but despite how many asterisks are found in coefficient charts, we should be skeptical of terrorism findings that are not robust across datasets, and given the discrepancies across data sets, such robustness may be unlikely. The long twilight struggle for cumulative knowledge continues.


3 thoughts on “Terrorism Data Remains a Mess

  1. Chris, consider cross-checking with fatalities – both civilian and security force – in Pakistan for the years in question. The problem is that there is both terrorism and insurgency in Pakistan (although the military tends to refuse to acknowledge the latter). What might be happening – and I don’t actually know if this is the case, again because the data is a bit funky – is that “terrorism” is down (because of how those types of attacks are defined) but deaths to insurgent violence are up. It may be that sectarian violence (terrorism) is still being captured, but that violence against the state itself is now being categorized (or operationalized) in ways that don’t fit the “terrorism” definition.

    • Thanks, Tim. It’s not easy to add graphs in the comments, or I would do so. In the GTD data, it’s fairly easy to decompose targets. There, the military as a target by itself has peaks in 2007 and a smaller one in 2011 (trough in between). The police have a small peak in 2007 and a bigger one in 2011 (trough in between). And the target category of “government (general)” is more or less a straight line increase since 2007. Since the NCTC WITS website is now deceased and it’s data is in .xml format, it’s relatively difficult for me to do something similar with that data, but I thought I’d at least give you the GTD results.

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