Determining Rent Value of Residential Multi-Family Units?

[Joel Bowen]

When purchasing a residential MF property, what other types of properties am I comparing the MF property to so that I can determine the rent value of each unit? Am I mainly focusing on apartment units that are in a certain location of the MF, if so how far away should I be looking for comparable units? OR am I comparing them only to other similar MF units in the area?

What are some other factors that can help me determine the rent value of each unit?