ISIS Foreign Fighters and the Origins Paradox

By the end of 2015, it was estimated that about 30.000 foreign fighters (FFs) had joined ISIS in Iraq and Syria. More recently and combining diverse data sources, the numbers went up to 41.490. While many FFs were recruited in Middle Eastern and Arab countries, nations such as Finland, Belgium and Sweden rank highest regarding FFs relative to Muslim population.
Explaining the amount of FFs leaving from each country constitutes an interesting endeavour and to a certain extent draws on radicalisation literature pointing to micro-, meso-, and macro-level determinants. The number of FFs per country is subsequently explained by social isolation, population, Muslim population, economic development, distance (to Syria), and a country’s involvement in the Global Coalition against Daesh. Despite these interesting findings, the question why countries such as Finland, Belgium and Sweden have the highest relative amount of FFs remains unanswered.
By means of a negative binomial count model, we focus on the importance of isolation and a perceived threat to the Muslim way of life to explain the amount of FFs for the countries where official data are available . As precise measures for isolation and threat perception are not readily available, we argument the value of multiple proxies, such as the KOF Globalisation index , and report their explanatory power.
Despite data limitations and econometric challenges, it is worth to further investigate this topic as a better understanding of the flow of FFs is important if we wish to respond appropriately to the threat that is still posed by some returning FFs.