Lean manufacturing practices: Do they work in American companies?

Abstract

Frederick Taylor revolutionized the workplace during the early twentieth century with his ideas on work organization and task decomposition. Since then, many organizational theorists have redefined management and workforce relations to improve productivity and worker satisfaction. Today, lean manufacturing concepts are widely accepted as the most effective way to manage manufacturing processes and attain a high degree of worker competency and dedication. The best known study designed to evaluate the impact of lean manufacturing was the International Motor Vehicle Program (IMVP). While comprehensive, critics maintain that the IMVP study did not directly assess causal relationships between lean production practices and related manufacturing and design performance measures. This dissertation is an empirical study of the theories and concepts of lean manufacturing grounded in an open systems theoretical framework. It assesses causal relationships between lean manufacturing and design practices and company performance. Five subsystem models are accessed: Human Organization, Production Technology and Methods, Quality System, Supplier System and Design System. Twenty-five manufacturing practices and six design practices are examined. The significance of lean manufacturing and design practices is determined by testing seventy-three hypotheses using seven performance measures: Shop-Floor Efficiency, Product Quality, Employee Grievances, Unscheduled Downtime, Supplier Performance, Initial Design Time and Significant Design Changes. The interaction between production worker influence and production strategies is assessed. Six hypotheses are tested using five manufacturing practices: Production Worker Involvement and Suggestions, Production Worker Authority, Just-In-Time Inventory Methods, Business System Automation and Preventative Maintenance. Empirical data used to test all seventy-nine hypotheses were collected through a comprehensive survey conducted in 1992 by the Midwest Manufacturing Technology Center at the Industrial Technology Institute. Two hundred forty-nine small manufacturing companies from four industries participated in the study. Thirty-seven causal relationships were supported using multiple regression techniques. In summary, shop-floor efficiency and product quality were increased by self-directed work teams, production worker involvement and just-in-time inventory methods. Supplier performance was increased by the use of sole source suppliers and long term contracts. Design performance was increased by the use of concurrent engineering teams and training. Finally, the interaction between production worker influence and production strategies proved to be significant.