A pair constraint is a constraint between staff members
For example, it prohibits one staff member, A, and another member B from working the same shift, or if A works the night shift, B should also work the night shift.
For details, see Pair constraint
in Uer manaul.
Nurse shift work schedule is a best seller
When the shift work schedule is announced, the staff’s biggest concern is who they will be paired with.
In my experience, there are two types of nurse managers, those who do not use the no-pair constraint at all and those who do.
I imagine that the head who does not use the no-pair rule at all is the one who does not accept likes and dislikes among staff members, while the head who defines the no-pair rule is the one who listens to some flexibility from staff members, but I do not know.
I understand that it depends on the policy of the master manager because even in the same workplace, there is a difference in defining/not defining depending on the master manager.
I am not trying to say it is good or bad, but it is a software requirement to be determined if needed.
Pair-prohibited constraints
Empirically, you can ban quite a lot of pairs. Some of our division heads have banned 20 pairs, and it worked fine.
The pair prohibition constraint can be viewed as a constraint that does not narrow the solution space so much.
Preceptor-preceptee
The nurse on the senior side is called a “preceptor,” and the nurse on the newer side is called a “preceptee."
In Scheduling Nurse, the preceptor-preceptee relationship is achieved using the “A then B constraint” in both directions.
This preceptor-preceptee differs from pair prohibition because it narrows the solution space, so careful use is required.
Pair constraints as a group.
Pair constraints are essentially personal constraints but can be extended to groups.
It is also possible to use years of experience as a parameter. For example, see here
in Constraint FAQs.