The therapist and client (or teacher and student, or parent and child) draw up a written agreement that includes behavioral goals the client hopes to achieve. it also specifies the positive consequences for reaching the goal

This is what is called the contingency contracting and it is used to promote positive behavior and serve as deterrent for the negative ones. This functions as any contract and can as stated be made between various parties. The contract states what behavior will be rewarded and in what conditions and what the reward will be.