Borderline personality disorder (BPD) is a diagnostic term used to describe a chronic pattern of maladaptive behaviors that may include emotional lability, impulsivity, and interpersonal difficulties. People experiencing BPD may impulsively engage in serious and potentially lethal self-harming behaviors as a means of coping with their distress. Accurately assessing risk is critical for choosing the best management and treatment strategies. We conducted a study to test whether training clinicians in the use of a tool for evaluating risk in BPD would translate into more accurate risk assessment in this patient group. We ran a training program for clinical staff employed in public mental health and evaluated whether it changed the way in which clinicians judged suicide and self-harm risk in patients diagnosed with BPD. This case discusses how we designed this study and what we learned along the way.