1. There are several theories that attempt to explain what makes a good leader, including trait theories, behavioral theories, situational theories, and contingency theories. 
2. Situational theories propose that leadership effectiveness depends on factors like the interaction between leaders and followers, the structure of the work, and elements of different situational theories like the Blake-Mouton Managerial Grid and Path-Goal Theory.  
3. Contingency theories assess a leader's style and suggest that certain styles may be more effective depending on aspects of the situation like leader-member relations, task structure, and position power.