Can we profile terrorists

What is the profile of a terrorist offender? 

profiling illustration.jpg


This question (alongside of “what is going on in the mind of a terrorist offender”) is asked more than any other question in the aftermath of a terrorist attack. And despite the simplicity of the question, it reflects a very complicated need to not only understand who a terrorist is, but also why we are unable to prevent it. Yet, despite the need for an answer to this question, “profiling” anything (let alone something as complex and varied as terrorism) is often a lot harder it seems. Hence, despite decades of efforts to “profile” terrorist offenders we remain unable to do so.

It is perhaps important that we look at one final point to show why “profiling” is trickier than it perhaps seems. I want you to imagine that you have a tool that can “profile” a terrorist – better yet, a tool that is accurate 90% of the time (pretty high, I am sure you will agree). Now, let us imagine that we are “profiling” people who are entering the United States and for every 1000 people who enter the country, 10 of them are terrorist offenders (1% which is admittedly much higher than the actual number!). Let us look at how these numbers play out in real time;

            Within the 1000 people who enter the airport there are four potential outcomes;

1.      True positive (people who are terrorists and who the tool identifies correctly)

2.      False Positives (people who are not terrorists who the tool identifies incorrectly)

3.      True negatives (people who are not terrorists and who the tool correctly identifies as not being terrorists)

4.      False negatives (people who are terrorists, but the tool incorrectly identifies them as not being terrorists).


This 2 x 2 square is common when we look at the effectiveness of any tool. Let us then look at how these four types play out with our tool and our hypothetical airport scenario:

So out of the 1000 people in an airport, only 1% are terrorists, which would mean only 10 people out of the 1000 are terrorists and 990 are not

But remember, our tool is only right 90% of the time, so out of the 10 terrorists we would only correctly identify 9 as terrorists and out of the 990 innocent people, we would only correctly identify 891 as actually innocent.

This means that 1 out of 10 terrorists would be incorrectly considered not to be dangerous and 99 out of 990 total innocent people would be misidentified as terrorists.

This is something we call the “low base rate problem” which means that even if we have factors that we can use to make a profile – the occurrence of terrorism is so rare that our “profile” will often lead to errors and noise.

So, when a terrorist attack occurs people often want to know why the terrorist offender wasn’t stopped sooner, or intercepted before they were able to undertake their attack. In trying to answer this question people often look to, or seek a “profile” as a way of helping us spot who, among many potential terrorists, will eventually engage in violence. But the issue is not that simple. In Forensic Psychology, we know that “profiles” are not always reliable because behavior is too diverse and with terrorism, perhaps one of the rarest types of crime, any profile will struggle because the chances of someone engaging in terrorism are so rare.