In a staff-authority relationship, the opinion of a specialist in one department to another is

In a staff-authority relationship, the opinion of a specialist in one department to another is typically considered an advice. An advice is a suggestion or recommendation offered by someone with specialized knowledge or experience to help another person make a decision or solve a problem. In this case, the specialist is not in a position of authority over the other department, but rather provides their expertise to assist decision-making. The receiving department can choose to accept or reject the advice, but it is not a directive or command that must be followed. Similarly, it is not a delegation, which would involve transferring authority or responsibility for a task or decision to someone else.