Bass (1990) who reviewed literature of the previous thirty years believes that the hunt for a true definition of leadership seems to be fruitless because the appropriate definition depends on the methodology used to observe leadership, the philosophical beliefs of the observer and the purposes of the definition.

He provides an overview of the definitions taken from the literature and classifies 13 different perspectives of leadership.

For example, the roles of leadership can be seen:

• as the focus of group processes,
• as a personality attribute,
• as the art of inducing compliance,
• as an exercise of influence,
• as a particular kind of act,
• as a form of persuasion,
• as a power relation,
• as an instrument of goal achievement,
• as an effect of group interaction,
• as a differentiated role,
• as the initiation of structure, or
• as some combination of all these (Bass, 1990, p. 20).

Four broad approaches about the nature of leadership have arisen from the research literature. For example, leadership as:

• a series of personal traits or attributes possessed by the leader,
• a relationship between the leader and the lead,
• a context-dependent phenomenon and
• a social construct (Bass, 1990).