Subsequent Phases of the Hawthorne Studies
The illumination studies were followed by a study in the relay room, where operators assembled relay switches. This phase of the study tried to test specific variables, such as length of workday, rest breaks, and method of payment. The results were basically the same as those of the illumination studies: each test period yielded higher productivity than the previous one. Even when the workers were subjected to the original conditions of the experiment, productivity increased. The conclusion was that the independent variables (rest pauses and so forth) were not by themselves causing the change in the dependent variable (output). As in the illumination experiments, something was still not being controlled that was causing the change in the dependent variable (output).
Still another phase was the bank wiring room study. As in the preceding relay room experiments, the bank wirers were placed in a separate test room. The researchers were reluctant to segregate the bank wiring group because they recognized that this would alter the realistic factory environment they were attempting to simulate. However, for practical reasons, the research team decided to use a separate room. Unlike the relay room experiments, the bank wiring room study involved no experimental changes once the study had started. Instead, an observer and an interviewer gathered objective data for study.