The second section, which reviews findings from the three research areas, begins with a two-by-two matrix—high and low criminogenic risk and high and low functional impairment—for considering appropriate supervision and treatment approaches for people with mental illnesses. Interventions and strategies that have been shown to improve outcomes and reduce recidivism for the general population of persons on probation or parole are reviewed. They include adherence to the RNR model (risk-needs-responsivity), which matches the intensity of supervision to the level of risk of recidivism, targets changeable risk factors by addressing needs, and matches modes of service to a person's abilities and styles. Other evidence-based approaches in this area include cognitive-behavioral treatment, which addresses irrational thoughts that lead to anger and antisocial behavior, and drug treatment in the community. Research also supports certain strategies for use by corrections officers: "firm-but-fair" relationships, compliance strategies that favor problem solving over threats of incarceration, and boundary spanning, in which officers develop knowledge about mental health and community resources, maintain relationships with clinicians, and advocate for services. Boundary spanning has been shown to increase linkages to treatment, but not to reduce recidivism, for people with mental illnesses on probation.