Why: The purpose of the critical items list is to focus management's attention on items that need to be resolved during the design phase as a corrective action loop for influencing the life time costs.
When: The list starts with the first design review as issues are disclosed in design reviews for reliability.
Where: The critical items list is presented to top level management as issues to be accepted or resolved before paper plans become steel and concrete.
These definitions are written by H. Paul Barringer and are also posted on his web site at www.barringer1.com