They are bureau or shift commanders. They sign off on every thing you do and everything that's done on their watch, as well as manage budgets very closely. Lieutenants tend to be morale specialists. They don't exercise regular supervision, but are called in when an employee is having problems of some sort or another. Their talents and leadership come into play when something unexpected happens.
Sergeants are first-level supervisors.
They are either stationhouse oriented or street oriented, depending upon how much they have abandoned the patrol officer's mentality. The sergeant rank is one of the most sought-after positions, and perhaps the hardest one to obtain if not gained by seniority alone. Police organizations are tall, hierarchical, quasi-military bureaucracies. One look at the tall-ness of the organization chart tells you this, and you can also infer that certain organizational principles like chain of command are going to be important in tall organizations. We'll take a look at discretion, and its power, in a later lecture, but nothing at this point should imply that police organizations are anything but hierarchical.