Leaders are most effective when they leverage others to the maximum extent possible.  As a leader, typically you take accountability for results, this is separate from taking responsibility. 

Leaders can rely on authority/granted power to get others to take on responsibility, (while they retain accountability).   However, it is important to note the use of earned power does not require the use of authority and the outcomes are often of a higher quality.  

Delegation

Delegation is the process of both motivating and empowering others to take on the responsibility to carry out specific activities.  While there is some discretion associated with the delegation the accountability remains with the delegator.

Typically delegation is based on a social or organizational hierarchy, however, skilled leaders can facilitate actions by others through the practice of influence. 

Influence

When you affect change in the actions, behaviors or options of others it is most likely through the exertion of influence.  You are able to motivate others to produce a result because they want to, not because they have to. 

Activities that arise through an act of influence will probably be of a higher quality.  This is because responsibility for the effort is not mandated but rather based on personal motivation.  

Intuitively, things other people want to do are more likely to succeed than things they have little choice about. 

Don’t Go it alone

As a leader, you are more likely to succeed both your and other expectations, that is meet your accountabilities and more, through effectively motivating and supporting those around you.