Shear span length, transverse reinforcement inside the shear span and height to shear span ratio are the main factors.

My review paper will be extremely helpful to you 

Article SHEAR STRENGTH OF RC DEEP BEAM PANELS – A REVIEW

Conference Paper Failure Modes of RC Deep Beam Panels

Beam height to width ratio, shear reinforcement in beam, Fcu, Fy of shear reinforcement, size and location of openings if exist, types of loading

you can calculate using the MCFT methods. For this, i suggest you read my paper "shear in modeling until fracture of the behavior of the RC beam"

Good papers Leon Raj

I recommend you read the following paper. It is a good job and a good reference.

I hope it helps.

Best regards.