Job assignments play a central role in the development of successful leaders. Cynthia McCauley in Developmental Assignments (2006), offers 10 characteristics of assignments that cause learning:

Unfamiliar responsibilities
Starting something new or making strategic changes
Fixing problems created by someone else
Dealing with employees who lack experience, are incompetent or are resistant to change
High stakes (tight deadlines, pressure from above, high visibility, responsibility for critical decisions)
Managing work that is broad in scope or large in size
Managing the interface with important groups outside the organization
Influence without authority
Working across cultures
Being responsible for the work of people of both genders and different racial and ethnic backgrounds.