Was there really a Hawthorne effect at the Hawthorne plant? An analysis of the original illumination experiments
Levitt and List recovered the original data of the Hawthorne lighting experiments, run at Western Electric's Hawthorne plant from 1924 to 1927 in three departments of women who assembled relays or wound coils. The widely repeated account, that output rose whenever the light was changed, did not match the records. Every lighting change began on a Monday, because the plant was closed on Sundays, and output was generally higher on Mondays than on Fridays and Saturdays and about as high on Mondays whether or not the light had been changed that day. The authors found only weak hints of subtler Hawthorne-type effects and note that the original design was weak.
Levitt and List recovered the original data of the Hawthorne lighting experiments, run at Western Electric's Hawthorne plant from 1924 to 1927 in three departments of women who assembled relays or wound coils. The widely repeated account, that output rose whenever the light was changed, did not match the records. Every lighting change began on a Monday, because the plant was closed on Sundays, and output was generally higher on Mondays than on Fridays and Saturdays and about as high on Mondays whether or not the light had been changed that day. The authors found only weak hints of subtler Hawthorne-type effects and note that the original design was weak.
Written from the full text as summarised from the Gwern.net copy of the journal paper, and NBER working paper 15016 abstract, 2026-11-02.
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Levitt, S. D., & List, J. A. (2011). Was there really a Hawthorne effect at the Hawthorne plant? An analysis of the original illumination experiments. American Economic Journal: Applied Economics, 3(1), 224-238. doi:10.1257/app.3.1.224 https://doi.org/10.1257/app.3.1.224