Terrorist Group Brutality and the Emergence of the Islamic State

Professor Phillips presents a study assessing the certainty with which terrorist groups can repeatedly inflict fatalities in terrorist attacks. The study shows several prominent cases like Algerian terrorism, Al-Qa`ida, the Taliban, the Lord’s Resistance Army (LRA) and the Islamic State (ISIS).


Camp for Saharawi Refugees, Algeria

We assess the certainty with which terrorist groups can repeatedly inflict fatalities in terrorist attacks. A terrorist group is particularly dangerous that can inflict higher levels of fatalities with more certainty than other groups. We develop a fatalities-to-variability (F-V) measurement statistic to shed some light on the risk-adjusted brutality of terrorist groups. A relatively high F-V ratio indicates that a terrorist group demonstrates a capability to inflict fatalities with less variable outcomes across attacks than other groups. An increasing F-V ratio indicates an enhancement of this capability. Terrorist groups observed to be increasing the F-V ratio oftheir actions may be special cause for concern, especially when F increases concomitant with decreases in V. We compute the F-V statistic for every terrorist group that was active during the period 2000 to 2008. We assess the results and compare the relative brutality of terrorist groups. We examine several prominent cases including Algerian terrorism, Al-Qa`ida, the Taliban, the Lord’s Resistance Army (LRA) and the Islamic State (ISIS). ISIS has been accorded considerable attention recently. However, its emergence as a terrorist group with a relatively high F-V ratio can be traced to as early as 2007.


The brutality of a terrorist group can be gauged from the average number of fatalities it inflicts. Although this is certainly the most direct way to compare the brutality of different groups, it does not tell us anything about the relative capability with which different groups inflict brutality. A group’s capability at inflicting brutality is not simply reflected in the group’s average brutality. Every attack method from which a terrorist group may choose is characterised by an expected number of fatalities and a level of risk or variability. During a year in which the number of fatalities inflicted by a particular group is high, the outcomes of the group’s attacks may simply be reflecting the generally positive relationship between average fatalities and variability that characterises all attacks and all attack methods. What is of more importance is the relative capability that terrorist groups display in managing this positive trade-off between and not simply the relative positions that terrorist groups take in trading off expected outcomes against risk. Some terrorist groups will demonstrate an ability to inflict the same number fatalities with less variability over time than other groups and some groups will demonstrate an ability to inflict increasing numbers of fatalities over time with stationary or decreasing variability. For these groups, the outcomes of their attacks become both more brutal and more certain. To identify these groups we can use the fatalities-to-variability ratio introduced in the previous chapter.


At the aggregate level, the fatalities-to-variability ratio can be thought of as being like a barometer for terrorism. When it increases, terrorists have been able to inflict more injuries and fatalities at every level of risk. When it decreases, terrorists have been able to inflict less. If the positive relationship between fatalities and risk is graphed, the fatalities-to-variability ratio is reflected in its slope. A steeper slope, a higher fatalities-to-variability ratio, means that terrorists have been able to inflict more injuries and fatalities at each level of risk. The oscillation of the ratio from year to year tells a story about terrorist brutality and capability. It may also tell a story about the effectiveness of counter-terrorism. This can be explained with the help of Figure 1. Here, two positively sloped lines are drawn. Each represents a possible trade-off between expected or average fatalities and variability that might characterise the terrorism context during some period of time. The steeper of the two, associated with the ratio 𝐹/𝑉2 , reflects a situation where terrorists have been able to inflict a higher average number of fatalities at each level of risk. For example, at risk level 𝑣1 terrorists can inflict 𝑓2 fatalities. The oscillation of the F/V ratio and the riskreward trade-off over time indicates how much risk must be borne by terrorist groups on average in order to inflict fatalities. Within a context described by a particular aggregate F/V ratio, we will find terrorists and terrorist groups that can inflict more fatalities at each level of risk than other groups. These groups have F/V ratios that lie above the risk-reward trade-off. Such a group, for example, may inflict an average number of fatalities greater than 𝑓2 whilst bearing a level of risk equivalent or less than 𝑣1 . This is a key indicator of superior capability. It is also an early indicator.


Although many examples may be brought to bear to highlight the usefulness of this measurement statistic as an early identification tool, the contemporary context finds no more prominent example than that which is accorded by Islamic State. The brutal nature of this group’s actions has been well documented but this documentation began quite some time after the group had already established itself as both a brutal group and a group with relatively superior capability at inflicting brutality. We shall say more about this later in this chapter but for now we can note that an early precursor to Islamic State, Islamic State of Iraq, demonstrated emerging superior capability as early as 2007. In that year, the group inflicted an average of approximately 8 fatalities per attack per month. The variability per attack was 13 fatalities. In 2008, the average was again approximately 8 fatalities per attack per month but the variability had fallen to around 10 fatalities. The outcomes of the group’s attacks were becoming less variable, more certain, but just as brutal. Other groups, including Al-Qaida in Iraq, were inflicting more fatalities per attack at this stage, as were other groups in other regions. However, the fatalities-to-variability ratio for the Islamic State of Iraq already placed it in the group of ten most capable groups of any region in 2007 and again in 2008. In another few years, the group would overtake Al-Qaida in Iraq in terms of capability and become both more brutal and more capable as it emerged formally as Islamic State. By 2011, the group was inflicting an average of more than 20 fatalities per attack with only about as much variability as its 2007 operations.


For each attack method that might be used by a terrorist group, there is a generally positive relationship between the average number of inflicted fatalities and the variability of the outcomes. The data for individual attack methods covered by the Global Terrorism Database (GTD) is presented in Table 1. This data includes all instances where these attack methods were used globally for the period 2000 to 2008. Just like in the previous chapter, there is a generally positive relationship between the average number of fatalities that can be expected to be inflicted by a particular attack method and the variability of the outcomes. A higher expected number of fatalities is accompanied by less certainty or a higher probability that the actual outcomes will diverge from that which was expected. The positive relationship between expected fatalities and risk is also reflected in the outcomes of the actions of individual terrorist groups.


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Keywords: terrorism, terrorist, terrorist group, risk, brutality, capability, transitory, persistent, fatalities, Algeria, Al-Qa`ida, Taliban, Lord’s Resistance Army, LRA, Islamic State, ISIS.


JEL Classification: D03, D74, H56, K42

Suggested Citation:

Phillips, Peter J., Terrorist Group Brutality and the Emergence of the Islamic State (August 12, 2014). Phillips, P.J. 2016. “Terrorist Group Brutality and the Emergence of the Islamic State.” In: Phillips, P.J. 2016. The Economics of Terrorism. Routledge, Abingdon, Oxon & New York, NY.

Available at SSRN: https://ssrn.com/abstract=2479740 or http://dx.doi.org/10.2139/ssrn.2479740Download


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