The main elements of the Scientific Management are [1] : "Time studies Functional or specialized supervision Standardization of tools and implements Standardization of work methods Separate Planning function Management by exception principle The use of "slide-rules and similar time-saving devices" Instruction cards for workmen Task allocation and large bonus for successful performance The use of the 'differential rate' Mnemonic systems for classifying products and implements A routing system A modern costing system etc. etc. " Taylor called these elements "merely the elements or details of the mechanisms of management" He saw them as extensions of the four principles of management.[2]