Business rules are encountered at many points during business process
improvement. They can constrain the value chain by imposing an overall
sequence on the high-level processes; they can constrain the business processes,
represented in the business process models or swimlane diagrams (Technique 37),
by imposing a need for a particular task to be carried out by a particular actor or
at a set point in the process, or even to be carried out at all; finally, they can
constrain the procedures followed during a task, by imposing rules upon which
decisions are based.