Her research is focused on evaluating preventative interventions for families, and particularly the role of parental mentalizing as a mechanism of change. She has carried out research evaluating the outcomes of psychoanalytic and mentalization based treatments for families experiencing complex difficulties, including interventions for parents in prison, parents with perinatal psychiatric difficulties, and families in the child welfare system. Dr Sleed is a trainer in various systems for coding the Parent Development Interview, including Parental Reflective Functioning and the Assessment of Representational Risk. She has used the measures extensively in clinical evaluations and therapy process research. Her research has also investigated and addressed issues of measurement of parental mentalization, particularly pre-mentalizing modes, in the assessment of relational trauma within the parent-child relationship.