Can we profile terrorists

What is the profile of a terrorist offender? 


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.


To understand why this profile is so difficult to define, perhaps it would help if we looked at what a profile is and how, typically, they are generated. Now, most of us were probably first introduced to the term “profile” through modern crime-dramas such as C.S.I., N.C.I.S., or Criminal Minds (which focusses on the F.B.I.’s behavioral analysis Unit). Here, the shows protagonists (who often show an aptitude for getting “inside” the mind of a criminal) often discuss the “profile” of a given type of criminal. Here, they may outline the jobs such people commonly hold, their lifestyle, how social they are, and if they are (or are not) likely to be currently known to police. In doing so, they are able to help the police prioritize their suspect pool by focusing on the individuals who fit the “profile” and are hence most likely to have committed the crime (spoiler alert: they usually catch the criminal). Unfortunately for us however, profiling in the real world is far less accurate.


In the real world, the most commonly used definition of “profiling” is provide by Blau (1994):

 “[Profiling is] basically a method of helping to identify the perpetrator of a crime based on an analysis of the nature of the offence and the manner in which it was committed. The process attempts to determine aspects of a criminal’s personality makeup from the criminal’s choice of action before, during, and after the criminal act. The personality information is combined with other pertinent details and physical evidence and then compared with characteristics of known personality types and mental abnormalities. From this, a working description of the offender is developed.”


Now, before we go any further, draw your attention to a very important aspect of this quote; “identifying the perpetrator of a crime based on the analysis of the offence.” Profiling, in the real world, occurs after a crime has occurred. This is often overlooked, but when we discuss the “profile” of a terrorist, more often than not we are talking about predicting who, out of a large pool of people, will in the future engage in a crime (not in the past). This lack of a crime is one of many reasons why we cannot profile a terrorist.

But let us look deeper because profiling itself (pre and post crime) is not as easy as our T.V. counterparts make it seem. Now for a profile to work we must satisfy two basic hypotheses:

1.      Behavioral Consistency

2.      Offender Homology (homology means something being similar or the same)


These two assumptions basically mean that people who commit crimes must behave consistently, and that people who engage in similar behaviors at a crime scene must have similar personalities. Because of the widespread use of Profiling, testing these two assumptions has been a central effort for Forensic Psychologists for the past few decades and unfortunately neither of these assumptions has a lot of support because people are not that consistent when they commit crimes (often because the environment has a strong influence on our behaviors). For example, say a criminal’s modus operandi was to dump their victim’s body in the water, but in one instance, someone enters the home before the criminal can take the body out of the home. The criminal has to jump out the window to avoid being caught and thus leaving the body inside. This environmental change could confuse investigators who would expect this type of criminal to hide the body.

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.