To assess the risk of harm, identify the workers affected and consider the duration (how long), frequency (how often) and severity (how severe the hazard and exposure) of their exposure. Hazards should be considered together because they interact or combine: a worker facing aggressive customers is more likely to be harmed when no one is present to support them and they cannot alter how they work. Risk rises with more severe exposure such as a traumatic incident, more frequent exposure such as regularly working without support, and longer exposure such as high demands over weeks or months, and combinations are worse, for example a short severe event on top of long low-level lack of support. Psychological injuries on average need longer off work and cost more than physical injuries. Appendix C helps capture the information.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.