Leaders can be appointed or elected. What criteria are used to make a selection in either case?

ratification by higher authority or election of where majority carries the vote respectively.

Explanation:

Appointments precedes nomination- here you look at for potential candidate; this is done usually by some one in power and according to the balance of power associated with the state; such nominees might need to be ratified [ confirmed by screening] by the legislators[ the law makers] in order for the appointment to take place.

In the case of been elected; an electioneering process- a means where people can cast their votes for candidates of their choice; is usually ensued. Picking this candidate could come from nomination or by indication of interest in vying for the position in question - this most times requires a financial obligation for indication of interest.

answer; proximity;