To appreciate how the theory of sampling arose, it helps to know a little about the problems it was designed to address. For most of human history every object was hand-crafted. Each complicated object was made by a specialist. There have been exceptions. The Egyptians, who constructed their largest, best-known pyramids over the course of just a few centuries, must have cut, transported, and piled the millions of large stone blocks required to make these monuments in a way that used at least a few assembly-line tech- niques. They also apparently standardized the construction of bows and arrows so that the weapons of one soldier were interchangeable with those of another. For the most part, however, societies were neither large enough nor organized enough to require the sort of mass production technology that dominates modern life.
The situation began to change during the Industrial Revolution. One of the first critical suggestions was offered by Eli Whitney, who is celebrated in American schools as the inventor of the cot- ton gin long after the purpose of a cotton gin has been forgotten. (A cotton gin is a device for separating cottonseeds from cotton fiber. Its invention made cotton the principal cash crop in the southern United States for many years.) Whitney suggested that guns—flintlock guns, to be specific—be manufactured in such a way that the parts from different rifles could be interchanged with one another. In 1798 the federal government awarded him a contract to produce 10,000 muskets using his Uniformity System, an early version of mass production.
This approach was in stark contrast to traditional methods. Previously, each part of a gun was created to fit the other parts of a particular gun. Of course, all guns of a certain type had charac- teristics in common. They were of roughly the same dimensions, and they worked on the same basic physical principles. But it was usually not possible to use one gun as a source of spare parts for another, even when both guns were created at roughly the same time by the same craftsperson. There was too much variation in the product. Whitney’s new method of manufacturing guns was meant to overcome this shortcoming, but it also pointed to a new method of manufacturing other objects as well.
This new manufacturing method required standardization of design and materials. It also required that the manufacturing process be sufficiently controlled that an object made at the begin- ning of the week would be “identical enough” to the object made at the end of the week to make them interchangeable. This change in the concept of manufacturing has changed the world. We are still grappling with its implications for labor and for our standard of living.
Throughout the 19th century, industrial engineers on both sides of the Atlantic worked to implement the new ideas. “Simple” objects such as nuts and bolts, textiles, and pulleys began to be manufactured according to standard designs using methods that greatly increased the quantity of finished goods, where the quantity is measured both in numbers and in the number of units per person engaged in the manufacturing process. Nor was this increase in production due solely to what was happening on the factory floor. Much of the culture and technology of the time was aimed at facilitating manufacturing operations. Steamships were plying the world’s oceans transport- ing raw materials to the manufacturing sites and finished goods from the manufacturing sites to consumers around the world. A great deal of money was changing hands, and this served to accelerate progress further.
Late in the 19th century the American engineer and inventor Frederick Winslow Taylor (1856–1915) began to search for more efficient production processes. Taylor, who had a degree in engi- neering from Stevens Institute of Technology, Hoboken, New Jersey, was interested in improving the human processes by which goods were manufactured. He studied the physical motions of workers involved in a manufacturing process and sought to stream- line them. He called his ideas “scientific management.” Taylor was quite successful. As a consequence of his work, productivity—the amount of goods produced per worker—soared again.
Many of these “hard” and “soft” technologies meshed together in the mind and factories of the American industrialist Henry Ford (1863–1947). Ford was engaged in producing what was, and arguably still is, the most technologically sophisticated consumer
item ever made, the automobile. To accomplish this he joined techniques of mass production and scientific management to pro- duce huge numbers of cars at a cost that many people could afford. This was a tremendous technical accomplishment because it involved the coordination of large numbers of workers, the acqui- sition of huge numbers of parts, and the design of an industrial process such that the quality of the final product was controlled from day to day and week to week.
Ford’s manufacturing technologies were quickly emulated and improved upon in many places around the world. Large, complex manufacturing concerns were producing ever-increasing amounts of consumer goods. As the complexity of the manufactured goods
Interior of the tool and die building at the Ford River Rouge plant, Dearborn, Michigan, 1941. Mass production of increasingly sophisticated goods demanded new statistical tools to establish and maintain control over industrial processes. (Office of War Information, Library of Congress, Prints and Photographs Division)
increased, controlling the quality of the items produced became increasingly difficult. How could one maintain control of the various processes and materials involved so that the quality of the finished product was uniform? How, in effect, could the right hand know what the left hand was doing?