Book review: What Makes a Terrorist

I just finished reading Alan Krueger's 2007 book, What Makes a Terrorist. This reading was timely, for two reasons: (1) Krueger passed away last month (see my post on his passing here); and (2) the recent mass shooting in Christchurch. Krueger's book is both a review of the relevant literature, and a report on his own related research, constructed from the three lectures he gave as part of the Lionel Robbins Memorial Lecture Series in 2006. Krueger defines terrorism as "premeditated, politically-motivated violence", and he limits his consideration to those acts "perpetrated by substate organizations and individuals with the intent of influencing an audience beyond the immediate victims". The 'substate' aspect of this is important, since it eliminates consideration of terrorism by states.

The first lecture looks at the individual factors associated with being a terrorist. Krueger motivates this section by noting that most people identify poverty or lack of education as a source of terrorism. Such a conceptualisation has a strong economic underpinning. Lower income people (or the unemployed) have a lower opportunity cost of time, so the income foregone by being a suicide bomber, or being jailed indefinitely for a terrorist act, is smaller for those with lower income or those who are unemployed (a similar argument can be made about crime more generally). I found the motivation here to be less than compelling. I don't think I had heard a strong argument for terrorism being associated with poverty, but instead being associated with differences in ideology. However, regardless of the motivation, Krueger finds that:

...the evidence is nearly unanimous in rejecting either material deprivation or inadequate education as an important cause of support for terrorism or of participation in terrorist activities. 

Instead, Krueger finds that terrorists are motivated by political goals.

The second lecture uses cross-country data to look at which countries have more terrorists, and which countries are more likely to be the targets of terrorist attacks. Here, Krueger finds that:

...civil liberties are an important determinant of terrorism... The data tell us that terrorism should be viewed more as a violent political act than as a response to economic conditions. Education and poverty probably have little to do with terrorism. There are many reasons for improving education and reducing poverty around the world, but reducing terrorism is probably not one of them.

Essentially, the cross-country results support the results from the analysis at the individual level. However, it is important to note that all of this research is correlational, rather than causal. These are simply the factors associated with terrorism, and it would take much more sophisticated methods to demonstrate that these correlations are causal, i.e. that a lack of civil liberties causes terrorism.

Finally, the third lecture looks at the consequences of terrorism. Do terrorist acts have a big impact on the economy, or do they impose psychological costs on the population? Maybe surprisingly, Krueger notes from a range of research that the impacts are small and not persistent:

The type of terrorism we have witnessed so far is comparably more to the situation the United States faced with the Barbary pirates in the late eighteenth century than to World War II: a risk for a small number of people that is not a major threat to most people's way of life or to national prosperity.

Essentially, while they may be some short-term impact on economic output (GDP) or on measures of subjective wellbeing, those effects disappear in the long term.

This book is relatively easy to read, especially for those with a little bit of background in economics. There are some technical parts, but Krueger doesn't allow them to bog down the narrative too much, and it is easy enough for the reader to gloss over the more technical aspects and focus on the substantive arguments. As an introduction to the literature (at least, up to 2006), I think this is a good book to read. It lacks a bit of the insight that an additional decade and more of research has provided, but is nevertheless interesting and informative.