Final answer:
Structured observation is useful when observing routine or repetitive behavior, such as in the Strange Situation procedure used to evaluate attachment styles between infants and caregivers.
Step-by-step explanation:
When you are observing routine or repetitive behavior, structured observation is useful. Structured observation involves observing individuals while they engage in set, specific tasks. For example, the Strange Situation procedure used to evaluate attachment styles between infants and caregivers is a form of structured observation.