Mikel Harry in my latest book, "Leading High Reliability Organizations in Healthcare," CRC Press 2016, shares the history of integrating the equation Y = f(x) into Six Sigma. In English, the equation can be read as "an outcome is a function of the inputs." Bill Smith and Mikel did not invent the equation, but found its message important in designing systems and solving problems and made it a part of every good training program. In agreement with Deming's scientific approach to improvement, one should focus on the inputs to get the outcome desired.
Have you ever been measured for an outcome and not sure what is driving the outcome? Or, not given the resources or empowerment to improve the inputs resulting in that outcome change expected? Supervisors measuring associates for an output without empowering them in the ability to find and improve the inputs is cruel, don't you think?
How does this equation work for you in really important things, like, "real life?"