How powerful is ISIS, really? Since 2014, we have been told that the group has lost 40% of its territory in Iraq, and a further 20% in Syria. In terms of soldiers and combatants, new estimates place the number of ISIS members in Iraq and Syria at between 19,000 and 25,000, a decrease from 33,000 in early 2015. However, it is clear the nature of the conflict is changing. Not only has ISIS influence spread to other states like Libya, but as a New York Times piece published this week makes clear, ISIS has been attempting to infiltrate and orchestrate attacks in Europe since mid-2014.

The video above from The Atlantic does a good job at breaking these numbers down, and examines the quandary in counting individuals inspired by the groups brand, and those controlled directly by the groups leadership. This is what makes quantifying the strength of ISIS difficult - how do you account for brand power? This is also a hint of how the conflict may evolve in the future. As the group gradually loses territory, manpower and material resources in Syria, Iraq and Libya, it will become increasingly important to counter its ideological appeal.