The original research involved workers who made electrical relays at the Hawthorne Works, a Western Electric plant in Cicero, Illinois. Between 1924 and 1927, the famous lighting study was conducted. Workers experienced a series of lighting changes in which productivity was said to increase with almost any change in the lighting. This turned out "not" to be true. In the study that was associated with Elton Mayo, which ran from 1928 to 1932, a series of changes in work structure were implemented (e.g., changes in rest periods) in a group of five women. But this was a methodologically poor, uncontrolled study that did not permit any firm conclusions to be drawn.