DeMatteo's goal is to identify ways to influence law, policy, and practice using social science research.
[3] At MCP Hahnemann University, his dissertation in fulfillment of graduation was "Psychopathy in a non-institutionalized population: Behavioral, personality, and affective characteristics.
[4] This dissertation was interested in the comparison of psychopathic characteristics between institutionalized and non-institutionalized individuals in the greater Philadelphia area.
[4] Before graduating with his PhD, DeMatteo was an adjunct instructor of psychology at Drexel and at his alma mater Rutgers.
[5] DeMatteo has consulted with both city and state agencies, legislators, correctional facilities, and law enforcement.
[3] He uses his research to conduct mental health assessments as well as testifying as an expert witness in state and federal courts.
"[8] DeMatteo has been an associate reviewer for the American Psychology-Law Society News, Journal of Forensic Psychology Practice, as well as Law and Human Behavior.