The staff member's role in relation to the student – for example:

• personal tutor
• supervisor
• dissertation supervisor

The student's role in relation to the staff member – for example:

• personal tutee
• research student
• dissertation supervisee

A unique ID to identify the relationship type – for example:

• personalTutor
• supervisor
• diss-supervisor

Prose description of the student relationship type, suitable for display in a UI – for example:

• Dissertation Supervisor
• Major Project Supervisor
• Personal Tutor

String suitable for use as a path/URL substitution variable – for example:

• tutor
• supervisor

Generally shouldn't contain special characters.