In the wake of 9/11 there was an explosion - no pun intended! - of interest in terrorism: what it was, what caused it, and, most importantly, what could we do to stop it. One of the niche efforts was that of 'risk assessment', a field that predated the events of September 2001, but was adapted to identify people at risk of adopting violent ideologies and acting upon them. Several such tools were created - but do they actually work and are they useful for practitioners (i.e. security intelligence and law enforcement agencies upon which we rely to act BEFORE terrorist acts occur). Borealis looks at this issue with Emily Corner, a professor of criminology at the Australian National University (ANU) in Canberra.