The name "elevator pitch" reflects the idea that it should be possible to deliver the summary in the time span of an elevator ride, or approximately thirty seconds to two minutes and is widely credited to Ilene Rosenzweig and Michael Caruso (while he was Editor for Vanity Fair) for its origin. The term itself comes from a scenario of an accidental meeting with someone important in the elevator. If the conversation inside the elevator in those few seconds is interesting and value adding, the conversation will either continue after the elevator ride, or end in exchange of business cards or a scheduled meeting.
One idea behind an elevator pitch is to be able to actually not only say what you do but do it in a way that is interesting. For eg. If you asked someone what they do and they answer I am a (financial planner) for example the conversation may almost end there. As the person who hears what they do may already feel they know what it is that person does. So it is important to be able to explain what you do in more detail but without using terminology that will pigeon hole you before you get started. 
- Pincus, Aileen. "The Perfect (Elevator) Pitch". Business week.
- Hahn, Gerald J. (1989), "Statistics-Aided Manufacturing: A Look Into the Future", The American Statistician 43 (2): 74–79, doi:10.2307/2684502, JSTOR 2684502.
- Peters, Tom (1999), "The Wow Project" (PDF), Fast Company 24: 116.
- "What is an Elevator Pitch?". Mind Your Pitch.