Maybe Workers Aren’t the Productivity Problem
Steve Mason ([email protected]), Tim Baines ([email protected]), and Mark Wilcox, “Manufacturing Systems and the Human Performance Fallacy,” Cranfield research paper. Click here.
In 1911, Frederick Winslow Taylor published The Principles of Scientific Management, in which he argued that workers were the primary cause of manufacturing inefficiency — and that the time they spent on tasks should be strictly controlled by managers. Inefficient workers have been blamed for low productivity ever since. But new research by three U.K.-based academics challenges this view.
Steve Mason, a researcher; Tim Baines, a senior lecturer; and Mark Wilcox, a lecturer, all at the Centre for Business Performance at Cranfield School of Management in the U.K., examined the impact of variations in worker performance on the efficiency of a manufacturing system.
Ten operations were monitored over a 12-week period across different worker shifts to determine how long it took workers to complete certain manual tasks on an automotive assembly line. The result was a data set of more than 200,000 instances of each manual task, which confirmed that each worker operated at a slightly different speed.
Then, using discrete event simulation — a type of computer modeling used in designing manufacturing systems — the researchers calculated the impact of these differences in worker performance as well as other factors, such as system breakdowns, on the overall output of the assembly line.
The results were revealing. System breakdowns alone reduced efficiency (measured by the system throughput capacity) by 12 percent. Compared with this, the variation in worker performance had very little impact, accounting for only a 1 percent difference in efficiency.
In other words, a modern assembly line is anything but the smooth operation predicted by designers; its efficiency can be diminished by its complexity. As the authors note, “Observation of the simulations and the real world system showed that the normal mode of operation is not one of constant material flow, but rather intermittent flow, due to the presence of bottlenecks and random breakdowns.”
In fact, when the researchers compared the actual performance of the automobile assembly line to that predicted by the simulation, they found it was 15 percent less efficient than the simulation predicted. The most likely reason, they said, was that the computer model lacked important data about breakdowns and component shortages. “The real system was often directly observed in a ‘shutdown’ state,” the authors write. “These states, sometimes lasting for an entire shift, were predominantly caused either by machine breakdowns or shortages of parts from the feeder lines.”
Clearly, this research has serious implications for the way manufacturing plants are designed and managed. The command-and-control management approach favored by Taylor — still widespread — assumes that workers are the weakest link in an otherwise flawless chain. But this does not appear to be the case. Indeed, the study provides new substantiation for the idea, enshrined in the Total Quality Management movement, that workers can make their greatest contribution through troubleshooting and problem solving.
Des Dearlove ([email protected]) is a business writer based in the U.K. Mr. Dearlove is the author of a number of management books and a regular contributor to strategy+business and The (London) Times.
Stuart Crainer ([email protected]) is a business writer based in the U.K. and a regular contributor to strategy+business. He and Des Dearlove founded Suntop Media, a publishing and training company providing business content for online and print publications.