Final answer:
The unit manager's first missed step in problem-solving was incorrect problem identification, as they assumed the issue was scheduling rather than issues with the team leader's patient assignments without consulting the staff.
Step-by-step explanation:
The unit manager's first missed step in problem-solving was incorrect problem identification. Instead of taking the time to understand the root cause of the issue with the evening staff, the manager assumed the problem was related to the need for time off and scheduled holidays without consulting the staff. By not engaging with the staff to understand their perspectives, the manager failed to identify that the real issue was with the team leader and the way patient assignments were being handled. Effective problem-solving often begins with a proper diagnosis of the problem, a step that requires listening and engaging with those experiencing the problem firsthand.