The concept of "Power of One" was first introduced to me by as the title of a booklet by author Penny Reynolds. While the booklet is out of print, I have several copies I've held on to, sharing them with contact center professionals in presentations of how the "Power of One" individual heavily influences service level achieved on any given interval. Brad Cleveland of ICMI summarizes the topic in his post UNDERSTANDING THE "POWER OF ONE"--AS IMPORTANT AS EVER.
I've used the concept in a variety of PowerPoint presentations, sharing the relationship with how quickly service level drops (and occupancy increases) with the loss of just a single representative. Recently, I turned to leveraging RStudio.com and Shinyapps.io to create a dynamic visualization of the concept. The application allows you to input your call volume, handle time, and target service level. The output tells you how many agents you need staffed to achieve the service level goal, and graphs the relationship between service level and occupancy. Finally, you can use a slider to demonstrate how sensitive service level and occupancy are to adding or subtracting 1, 2 or 3 agents:
Enjoy modeling with the "Power of One" Shinyapp. Drop me a note if you find it useful in visualizing the concept!