Final answer:
Elizabeth seems to be practicing the 'structural change' technique, which focuses on altering family dynamics that may contribute to individual problems like addiction.
Step-by-step explanation:
Elizabeth, as a family therapist who notes that Roy's cocaine addiction is related to the dynamics within the family, likely practices the technique known as structural change. This approach in family therapy focuses on understanding and changing the relationships and hierarchies within the family system that may contribute to individual problems, such as addiction. This is distinct from techniques such as scaling, which is more about assessing severity or progress, client-centered therapy, which emphasizes an individual-focused, empathetic therapeutic relationship facilitated by the therapist, or reframing, which is about reinterpreting problems in a new, more positive light.