As Counter-Insider Threat (C-InT) programs begin to include concerns about workplace violence, they must be equipped to effectively assess and manage the associated risks. The current gold standard is structured professional judgment (SPJ), an evidence-based approach that combines empirically validated tools with professional judgment. The objective of this project was to produce a Reference Guide to educate C-InT professionals about the use of SPJ tools in violence risk assessment (VRA) and threat assessment (TA).