A method of evaluating the efficiency of an automatic machine, whereby, upon completion of a given production lot, a current performance index achieved by the automatic machine during manufacture of the production lot is calculated; and the current performance index is memorized in a nonvolatile memory, together with various characteristic parameters relating to the processing performed. To evaluate the efficiency of the automatic machine, the current performance index is compared with historic performance indexes memorized previously during operation of the automatic machine and having characteristic parameters substantially similar to the characteristic parameters of the current performance index.