Unless you try to do something beyond what you have
already mastered, you will never grow.


Ralph Waldo Emerson

The metaphoric phrase "(to) raise the bar," or "raising the bar," is an expression used to convey the idea of gradually setting the accepted minimum standards higher in order to reach an objective of excellence. As metaphors go, this is one that is still very true to its origin, and relatively transparent in its meaning.

The term came into common usage in the English language through the track and field sports of high jumping and pole vaulting, where athletes run and jump to propel themselves over obstacles. In each subsequent round of competition, the bar which establishes the vertical height of the obstacle is raised, making the event slightly more challenging. The athlete who displays the greatest stamina and skill successfully crosses the highest bar (or series of them), and wins the event.

As applied to life outside of the sporting world, raising the bar most often pertains to setting ever higher expectations of quality or quantity. These expectations may originate externally, imposed by others who are judging performance, or internally, as a method of self improvement. Ideally, the two work in tandem to bring about a new level of achievement unseen in the context of previous measures of excellence.


Reference source:
http://www.word-detective.com/