42 · Researching
Hawthorne Effect
People may act differently when they know they're being studied.
Evidence: DisputedWhat we do with it
- 01
Expect some performing in any session where people know they're watched. Look hardest at where they get stuck.
- 02
Check what you see in a session against the live product: analytics, support tickets, search logs.
- 03
Don't wave away an awkward result as “just the Hawthorne effect”. The effect is sometimes real, often small, and never a blanket excuse.
Examples
Getting it wrong, getting it right.
Don't
Dismissing a failed test with “they were only nervous because we were watching”.
Do
Check the same step in the live analytics. If people drop off there too, the problem is real.
The evidence
What the research says.
The original story doesn't survive a look at the data. John Adair's 1984 review found that the Hawthorne studies themselves don't show the effect, and that of 13 later studies set up to produce it, only 4 did. Steven Levitt and John List found the lost lighting records and reported in 2011 that the famous patterns were “entirely fictional”, with only faint hints of an effect. A 2014 review of 19 studies by Jim McCambridge and colleagues found that being studied can change behavior, but couldn't say when or by how much.
How our view changed
We don't wave away awkward results with it. We check what we saw in a session against what people do in the live product.
Sources
- Adair, J. G. (1984). The Hawthorne effect: A reconsideration of the methodological artifact. Journal of Applied Psychology, 69(2).
- 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).
- McCambridge, J., Witton, J., & Elbourne, D. R. (2014). Systematic review of the Hawthorne effect: New concepts are needed to study research participation effects. Journal of Clinical Epidemiology, 67(3).
Last reviewed November 7, 2026. How we keep this current