A layman’s perspective on the 1.5 Sigma Shift
To understand the math behind the 1.5 sigma shift in project management statistics, consider a desired goal which has to be achieved within a particular environment and certain environmental conditions.
1) Any goal or result will have to be planned keeping 2 things in mind:
a. The goal itself under standard environmental conditions
b. Changing environmental conditions which may result in variation
However stable any process is, over an extended period of time, the environmental conditions change, which causes variation. Thus at the planning stage, these environmental changes need to be balanced by a compensation factor in order to account for these changes to ensure that the long term goal is met.
When expressed in an equation format, the following is obtained
“Short Term Goal = Long Term Goal + Appropriate Compensation Factor for Environmental Changes"