This formula is especially relevant to determining cause and effect as well as measuring for improvement. It reads Y is a function of X. The Y is the effect of the problem or desired improvement and the X’s are the possible causes or areas affecting improvement.
For example, Y= total time for an output to go through the process and possible X’s are the time for each process step, wait time for delays, or volume going through the process at a peak time. Each of the X’s can be measured to understand their impact on the Y.
Selecting the X’s that have the strongest relationship to an improvement in Y are the root causes to be addressed in a solution.