Given the scale of challenges posed by the threat of terrorism and the perpetually limited resources available to counter terrorism, there is widespread agreement – if on nothing else - on the fact that there is an urgent need to find ways to prioritise the use of those resources. In this research note we argue that a greater consideration of the role of psychology in the development of risk assessment procedures may well be a useful tool to enable such prioritisation in a number of critical areas. It ought to be noted at the outset that there are many obvious challenges facing efforts to design risk assessment tools. Questions necessarily emerge about who needs to be assessed for risk and additionally - stemming from the conceptual confusion over what is meant by terrorism, and by extension, extremism - we might also wonder what is being risk-assessed? And finally then, we might ask what factors are related to the level of risk posed, and how we might identify these. At present we do not have complete answers to all of these questions, but this research note aims to explore some of these issues as a first step in the design of risk assessment tools for development in counter-terrorism.