A rule of thumb is a principle with broad application that is not intended to be strictly accurate or reliable for every situation.1 It is based not on theory but on practical experience.
FW Taylor, who is often called "The Father of Scientific Management," proposed four scientific principles of management to solve problems in the organization. His focus was to improve efficiency of workers and have optimum utilization of resources. His first principle was to "replace rule-of-thumb methods with methods based on scientific study...."2
Next: Heuristics
1 https://en.wikipedia.org/wiki/Rule_of_thumb2 http://www.netmba.com/mgmt/scientific/
