Goleman's study suggests that leaders who have mastered Authoritative, Democratic, Affiliative and coaching styles have the best climate and have the highest performance.
Effective leaders have the flexibility to switch among these leadership style as needed.
This ability depends on a person's emotional intelligence.
Emotional intelligence is the ability to understand and manage our relationship and ourselves better. Although our intelligence (IQ) is largely genetic, Emotional intelligence can be learned (and improved) at any age.
Source :- Daniel Goleman, Learning to Lead with Emotional Intelligence, Harvard Business Review March 2000.