The Production Recommendation Engine is a methodology for identifying the most important factor i.e. Constraint that stands in the way of achieving a goal and then systematically improving that constraint until it is no longer the limiting factor.
In manufacturing, the constraint is often referred as a bottleneck and there is always at least one constraint, and PRE uses a focusing process to identify the constraint and restructure the rest of the organization around it.
PRE adopts the common idiom “A chain is no stronger than its weakest link”. This means that processes, organizations etc are vulnerable because the weakest part can always damage or break them or adversely affect the outcome.