The determination of national productivity levels of machine tool inventories using productivity criteria quotients

Publication Date


Document Type


First Advisor

Hackamack, Lawrence C. (Lawrence Carroll), 1921-

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Management




Obsolescence of machine tool inventories is a critical problem for both nations and individual companies. This study has provided a measure of machine tool obsolescence on a national level by coopering the productivity index of industrial machine tool inventories with the productivity index of current vintage machines. The study has also provided the bools for on individual company to compare the productivity index of its machine tool inventory with the productivity index of the industry's inventory which the company is a part. The technique which enabled the determination of productivity indices was found in Productivity Criteria Quotients, or PCO. PCO is a measure of the changes in machine tool productivity capabilities resulting from changes of basic engineering design. The PCO value for a particular machine tool is a whole number dependent on the year of manufacture and independent of the manufacturer, PCO values of twelve machine tool types for the years 1940 to 1963 inclusive were used in the study. An inventory's productivity index, or average PCO, was determined by multiplying the number of machines of each vintage between 1940 and 1963 by the PCO for the respective year, and dividing by the total number of machines to arrive at an average. The age of machine tools in inventory was determined by a series of American Machinist inventory surveys and original shipment data. The conclusion of the study was that the average PCO of industrial machine tool inventories was lagging farther and farther behind the PCO of new machine tools as time progressed, indicating that government policies and present theories on machine tool replacement policy do not vigorously encourage the maintenance of productivity. This study has not established the number of years an inventory's productivity should lag the productivity of new machines. It has indicated, however, the existence of a trend towards increased lag, or increasing obsolescence.


Includes bibliographical references.


80 pages




Northern Illinois University

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